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  • 1. Cai, J
    et al.
    Guo, D.
    Khater, M
    Lavoie, C.
    Zhen, Zhang
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Solid State Electronics.
    SCHOTTKY FET FABRICATED WITH GATE LAST PROCESS2010Patent (Other (popular science, discussion, etc.))
  • 2. Cai, M.
    et al.
    Lavoie, C.
    Ozcan, A.
    Yang, B.
    Zhen, Zhang
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Solid State Electronics.
    SEMICONDUCTOR DEVICE WITH REDUCED JUNCTION LEAKAGE AND AN ASSOCIATED METHOD OF FORMING SUCH A SEMICONDUCTOR DEVICE2010Patent (Other (popular science, discussion, etc.))
  • 3.
    Cao, Qing
    et al.
    IBM Watson Research.
    Han, Shu-Jen
    IBM Watson Research.
    Tersoff, Jerry
    IBM Watson Research.
    Franklin, Aaron
    IBM Watson Research.
    Zhu, Yu
    IBM Watson Research.
    Zhang, Zhen
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Solid State Electronics. IBM Watson Research.
    Tulevski, George
    IBM Watson Research.
    Tang, Jianshi
    Haensch, Wilfried
    End-Bonded Mo2C Contacts for Carbon Nanotube Transistors with Low, Size-Independent Resistance2015In: Science, ISSN 0036-8075, E-ISSN 1095-9203Article in journal (Refereed)
  • 4. Chang, J.
    et al.
    Lavoie, C.
    Zhen, Zhang
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Solid State Electronics.
    SOURCE/DRAIN TECHNOLOGY FOR THE CARBON NANO-TUBE/GRAPHENE CMOS WITH A SINGLE SELF-ALIGNED METAL SILICIDE PROCESS2010Patent (Other (popular science, discussion, etc.))
  • 5.
    Chen, Xi
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Solid State Electronics.
    Chen, Si
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Solid State Electronics.
    Hu, Qitao
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Solid State Electronics.
    Zhang, Shi-Li
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Solid State Electronics.
    Solomon, Paul
    IBM T. J. Watson Research Center, Yorktown Heights, New York 10598, USA.
    Zhang, Zhen
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Solid State Electronics.
    Device noise reduction for Silicon nanowire field-effect-transistor based sensors by using a Schottky junction gate2019In: ACS sensors, ISSN 2379-3694, Vol. 4, no 2, p. 427-433Article in journal (Refereed)
    Abstract [en]

    The sensitivity of metal-oxide-semiconductor field-effect transistor (MOSFET) based nanoscale sensors is ultimately limited by noise induced by carrier trapping/detrapping processes at the gate oxide/semiconductor interfaces. We have designed a Schottky junction gated silicon nanowire field-effect transistor (SiNW-SJGFET) sensor, where the Schottky junction replaces the noisy oxide/semiconductor interface. Our sensor exhibits significantly reduced noise, 2.1×10-9 V2µm2/Hz at 1 Hz, compared to reference devices with the oxide/semiconductor interface operated at both inversion and depletion modes. Further improvement can be anticipated by wrapping the nanowire by such a Schottky junction thereby eliminating all oxide/semiconductor interfaces. Hence, a combination of the low-noise SiNW-SJGFET sensor device with a sensing surface of the Nernstian response limit holds promises for future high signal-to-noise ratio sensor applications.

  • 6.
    Chen, Xi
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Solid State Electronics.
    Chen, Si
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Solid State Electronics.
    Solomon, Paul
    IBM Corp, Div Res, TJ Watson Res Ctr, Yorktown Hts, NY 10598 USA.
    Zhang, Zhen
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Solid State Electronics.
    Top-bottom gate coupling effect on low frequency noise in a Schottky junction gated silicon nanowire field-effect transistor2019In: IEEE Journal of the Electron Devices Society, ISSN 2168-6734, Vol. 7, p. 696-700Article in journal (Refereed)
    Abstract [en]

    In this letter, strong low frequency noise (LFN) reduction is observed when the buried oxide (BOX)/silicon interface of a Schottky junction gated silicon nanowire field-effect transistor (SJGFET) is depleted by a substrate bias. Such LFN reduction is mainly attributed to the dramatic reduction in Coulomb scattering when carriers are pushed away from the interface. The BOX/silicon interface depletion can also be achieved by sidewall Schottky junction gates in a narrow channel SJGFET, leading to an optimal LFN performance without the need of any substrate bias.

  • 7.
    Chen, Xi
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Solid State Electronics.
    Chen, Si
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Solid State Electronics.
    Zhang, Shi-Li
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Solid State Electronics.
    Solomon, Paul
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Solid State Electronics. IBM Thomas J. Watson Research Center.
    Zhang, Zhen
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Solid State Electronics.
    Low-Noise Schottky Junction Trigate Silicon Nanowire Field-effect Transistor for Charge Sensing2019In: IEEE Transactions on Electron Devices, ISSN 0018-9383, E-ISSN 1557-9646, Vol. 66, no 9, p. 3994-4000Article in journal (Refereed)
    Abstract [en]

    Silicon nanowire (SiNW) field-effect transistors (SiNWFETs) are of great potential as a high-sensitivity charge sensor. The signal-to-noise ratio (SNR) of an SiNWFET sensor is ultimately limited by the intrinsic device noise generated by carrier trapping/detrapping processes at the gate oxide/silicon interface. This carrier trapping/detrapping-induced noise can be significantly reduced by replacing the noisy oxide/silicon interface with a Schottky junction gate (SJG) on the top of the SiNW. In this paper, we present a tri-SJG SiNWFET (Tri-SJGFET) with the SJG formed on both the top surface and the two sidewalls of the SiNW so as to enhance the gate control over the SiNW channel. Both experiment and simulation confirm that the additional sidewall gates in a narrow Tri-SJGFET indeed can confine the conduction path within the bulk of the SiNW channel away from the interfaces and significantly improve the immunity to the traps at the bottom buried oxide/silicon interface. Therefore, the optimal low-frequency noise performance can be achieved without the need for any substrate bias. This new gating structure holds promises for further development of robust SiNWFET-based charge sensors with low noise and low operation voltage.

  • 8.
    Chen, Xi
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Solid State Electronics.
    Hu, Qitao
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Solid State Electronics.
    Chen, Si
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Solid State Electronics.
    Netzer, Nathan L.
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Solid State Electronics.
    Wang, Zhenqiang
    Univ South Dakota, Dept Chem, Churchill Haines Labs, Room 115,414 East Clark St, Vermillion, SD 57069 USA.
    Zhang, Shi-Li
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Solid State Electronics.
    Zhang, Zhen
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Solid State Electronics.
    Multiplexed analysis of molecular and elemental ions using nanowire transistor sensors2018In: Sensors and actuators. B, Chemical, ISSN 0925-4005, E-ISSN 1873-3077, Vol. 270, p. 89-96Article in journal (Refereed)
    Abstract [en]

    An integrated sensor chip with silicon nanowire ion-sensitive field-effect transistors for simultaneous and selective detection of both molecular and elemental ions in a single sample solution is demonstrated. The sensing selectivity is realized by functionalizing the sensor surface with tailor-made mixed-matrix membranes (MMM) incorporated with specific ionophores for the target ions. A biomimetic container molecule, named metal-organic supercontainer (MOSC), is selected as the ionophore for detection of methylene blue (MB+), a molecular ion, while a commercially available Na-ionophore is used for Na+, an elemental ion. The sensors show a near-Nernstian response with 56.4 ± 1.8 mV/dec down to a concentration limit of ∌1 ΌM for MB+ and 57.9 ± 0.7 mV/dec down to ∌60 ΌM for Na+, both with excellent reproducibility. Extensive control experiments on the MB+ sensor lead to identification of the critical role of the MOSC molecules in achieving a stable and reproducible potentiometric response. Moreover, the MB+-specific sensor shows remarkable selectivity against common interfering elemental ions in physiological samples, e.g., H+, Na+, and K+. Although the Na+-specific sensor is currently characterized by insufficient immunity to the interference by MB+, the root cause is identified and remedies generally applicable for hydrophobic molecular ions are discussed. River water experiments are also conducted to prove the efficacy of our sensors.

  • 9.
    Chen, Xi
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Solid State Electronics.
    Zhang, Tao
    NanoBeam Limited, Cambridge CB1 3HD, England, United Kingdom.
    Constantoudis, Vassilios
    NCSR Demokritos, Inst Nanosci & Nanotechnol, Attiki, Greece;Nanometrisis PC, Attiki, Greece.
    Zhang, Shi-Li
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Solid State Electronics.
    Zhang, Zhen
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Solid State Electronics.
    Aged hydrogen silsesquioxane for sub-10 nm line patterns2016In: Microelectronic Engineering, ISSN 0167-9317, E-ISSN 1873-5568, Vol. 163, p. 105-109Article in journal (Refereed)
    Abstract [en]

    Hydrogen silsesquioxane (HSQ) has been used as a negative tone resist in electron beam lithography to define sub-10 nm patterns. The spontaneous polymerization in HSQ usually called aging in this context, sets a restricted period of time for a vendor-warranted use in patterning such small features with satisfactory line-edge roughness (LER). Here, we study the effect of HSQ aging on sensitivity and LER by focusing on exposing line patterns of 10 nm width in various structures. The results show that the 10 nm lines are easily achievable and the LER of the patterned lines remains unaltered even with HSQ that is stored 10 months beyond the vendor-specified expiration date. However, an increasingly pronounced decrease with time of the threshold electron dose (D-th), below which the line width would become less than 10 nm, is observed. After the HSQ expiration for 10 months, the 10 nm lines can be manufactured by reducing D-th to a level that is technically manageable with safe margins. In addition, the inclusion of a prebaldng step at 220 degrees C to accelerate the aging process results in a further reduced D-th for the 10 nm lines and thereby leads to a shortened writing time. The time variation of D-th with respect to the vendor-specified production date of HSQ is found to follow an exponential function of time and can be associated to the classical nucleation-growth polymerization process in HSQ.

  • 10.
    Cheng, K.
    et al.
    IBM research.
    Dennard, R.
    IBM Research.
    Zhang, Z.
    IBM Research.
    SEMICONDUCTOR DEVICE INCLUDING DUAL-LAYER SOURCE/DRAIN REGION2015Patent (Other (popular science, discussion, etc.))
  • 11. Cheng, K
    et al.
    Khakifirooz, A.
    Kulkarni, P.
    Ponoth, S.
    Kumar, A.
    Adam, T.
    Reznicek, A.
    Loubet, N.
    He, H.
    Kuss, J.
    Wang, M.
    Levin, T.
    Monsieur, F.
    Liu, Q.
    Sreenivasan, R.
    Cai, J.
    Kimball, A.
    Mehta, S.
    Luning, S.
    Zhu, Y.
    Zhu, Z.
    Yamaoto, T.
    Bryant, A.
    Lin, C.
    Naczas, S.
    Jagannathan, H.
    Edge, L.
    Allegret-Maret, S.
    Dube, A.
    Kanakasabapathy, S.
    Schmitz, S.
    Inada, A.
    Seo, S.
    Raymond, M.
    Zhen, Zhang
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Solid State Electronics.
    Yagishita, A.
    Demarest, J.
    Li, J.
    Hopstaken, M.
    Berliner, N.
    Upham, A.
    Johnson, R.
    Holmes, S.
    Standaert, T.
    Smalley, M.
    Zamdmer, N.
    Ren, Z.
    Wu, T.
    Bu, H
    Paruchuri, V.
    Sadana, D.
    Narayanan, V.
    Haensch, W.
    O'Neill, J.
    Hook, T.
    Khare, M.
    Doris, B.
    ETSOI CMOS for System-on-Chip Applications Featuring 22nm Gate Length, Sub-100nm Gate Pitch, and 0.08mm2 RAM Cell2011Conference paper (Refereed)
  • 12. Fletcher, B.
    et al.
    Lavoie, C.
    Maurer, S.
    Zhen, Zhang
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Solid State Electronics.
    A METHOD TO ENABLE THE PROCESS AND ENLARGE THE PROCESS WINDOW FOR THE SILICIDAITION OF SUSPENDED SI STRUCTURES WITH EXTREMELY SMALL DIMENSION2011Patent (Other (popular science, discussion, etc.))
  • 13. Fritz, G.
    et al.
    Pyzyna, A.
    Zhen, Zhang
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Solid State Electronics.
    Liu, F.
    Guillorn, M.
    Rodbell, K.
    Wisnieff, R.
    Interconnect Material Choices for Future Scaled Devices2012Conference paper (Refereed)
  • 14.
    Gao, Xindong
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Solid State Electronics.
    Andersson, Joakim
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Solid State Electronics.
    Kubart, Tomas
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Solid State Electronics.
    Nyberg, Tomas
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Solid State Electronics.
    Smith, Ulf
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Solid State Electronics.
    Lu, J.
    Hultman, L.
    Kellock, A.
    Zhen, Zhang
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Solid State Electronics.
    Lavoie, C.
    Zhang, Shi-Li
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Solid State Electronics.
    Epitaxy of Ultrathin NiSi2 Films with Predetermined Thickness2011In: Electrochemical and solid-state letters, ISSN 1099-0062, E-ISSN 1944-8775, Vol. 12, p. H268-H270Article in journal (Refereed)
  • 15. Guillorn, M.
    et al.
    Chang, J
    Pyzyna, A.
    Engelmann, S.
    Glodde, M.
    Joseph, E.
    Bruce, R.
    Ott, J.
    Majumdar, A.
    Liu, F.
    Brink, M.
    Bangsaruntip, S.
    Khater, M.
    Lauer, I
    Duch, E.
    Lavoie, C.
    Zhen, Zhang
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Solid State Electronics.
    Newbury, J.
    Kratschmer, E.
    Klaus, D.
    Bucchignano, J.
    To, B.
    Graham, W.
    Sikorski, E.
    Narayanan, V.
    Fuller, N.
    Haensch, W.
    A 0.021 mm2 trigate SRAM cell with aggressively scaled gate and contact pitch2011Conference paper (Refereed)
  • 16. Guillorn, M.
    et al.
    Joseph, E
    Liu, F.
    Zhen, Zhang
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Solid State Electronics.
    SILICIDE MICROMECHANICAL DEVICE AND METHODS TO FABRICATE SAME2011Patent (Other (popular science, discussion, etc.))
  • 17.
    Hinnemo, Malkolm
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Solid State Electronics.
    Makaraviciute, Asta
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Solid State Electronics.
    Ahlberg, Patrik
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Solid State Electronics.
    Olsson, Jörgen
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Solid State Electronics.
    Zhang, Zhen
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Solid State Electronics.
    Zhang, Shi-Li
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Solid State Electronics.
    Zhang, Zhi-Bin
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Solid State Electronics.
    Protein sensing beyond the Debye Length Using Graphene Field-effect Transistors2018In: IEEE Sensors Journal, ISSN 1530-437X, E-ISSN 1558-1748, Vol. 18, no 16, p. 6497-6503Article in journal (Refereed)
    Abstract [en]

    Sensing biomolecules in electrolytes of high ionic strength has been a difficult challenge for field-effect transistor-based sensors. Here, we present a graphene-based transistor sensor that is capable of detection of antibodies against protein p53 in electrolytes of physiological ionic strength without dilution. As these molecules are much larger than the Debye screening length at physiological ionic strengths, this paper proves the concept of detection beyond the Debye length. The measured signal associated with the expected specific binding of the antibodies to p53 is concluded to result from resistance changes at the graphene-electrolyte interface, since a sensor responding to resistance changes rather than charge variations is not limited by Debye screening. The conclusion with changes in interface resistance as the underlying phenomena that lead to the observed signal is validated by impedance spectroscopy, which indeed shows an increase of the total impedance in proportion to the amounts of bound antibodies. This finding opens up a new route for electrical detection of large-size and even neutral biomolecules for biomedical detection applications with miniaturized sensors.

  • 18.
    Hu, Qitao
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Solid State Electronics.
    Chen, Si
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Solid State Electronics.
    Zhang, Shi-Li
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Solid State Electronics.
    Solomon, Paul
    IBM T. J. Watson Research Center, Yorktown Heights, New York 10598, USA.
    Zhang, Zhen
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Solid State Electronics.
    Effects of Substrate Bias on Low-Frequency Noise in Lateral Bipolar Transistors Fabricated on Silicon-on-Insulator Substrate2019In: IEEE Electron Device Letters, ISSN 0741-3106, E-ISSN 1558-0563Article in journal (Refereed)
  • 19.
    Hu, Qitao
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Solid State Electronics.
    Chen, Xi
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Solid State Electronics.
    Norström, Hans
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Solid State Electronics.
    Zeng, Shuangshuang
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Solid State Electronics.
    Yifei, Liu
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Solid State Electronics.
    Fredrik, Gustavsson
    Swerea KIMAB, Stockholm, Sweden.
    Zhang, Shi-Li
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Solid State Electronics.
    Chen, Si
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Solid State Electronics.
    Zhang, Zhen
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Solid State Electronics.
    Current gain and low-frequency noise of symmetriclateral bipolar junction transistors on SOI2018Conference paper (Refereed)
    Abstract [en]

    This paper presents a comprehensive study ofsymmetric lateral bipolar junction transistors (LBJTs) fabricatedon SOI substrate using a CMOS-compatible process; LBJTs findmany applications including being a local signal amplifier forsilicon-nanowire sensors. Our LBJTs are characterized by a peakgain (β) over 50 and low-frequency noise two orders ofmagnitude lower than what typically is of the SiO2/Si interfacefor a MOSFET. β is found to decrease at low base current due torecombination in the space charge region at the emitter-basejunction and at the surrounding SiO2/Si interfaces. This decreasecan be mitigated by properly biasing the substrate.

  • 20.
    Hu, Qitao
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Solid State Electronics.
    Zhang, Shi-Li
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Solid State Electronics.
    Chen, Si
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Solid State Electronics.
    Zhang, Zhen
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Solid State Electronics.
    Symmetric Lateral Bipolar Transistors as Low Noise Signal Amplifier2019Conference paper (Other academic)
  • 21.
    Jablonka, Lukas
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Solid State Electronics.
    Abedin, Ahmad
    Department of Electronics, KTH Royal Institute of Technology, SE-16440 Stockholm, Sweden.
    Hellström, Per-Erik
    Department of Electronics, KTH Royal Institute of Technology, SE-16440 Stockholm, Sweden.
    Zhang, Shi-Li
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Solid State Electronics.
    Zhang, Zhen
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Solid State Electronics.
    A novel route to a reliable extraction of the specific contact resistivity of the germanium/nickel germanide interfaceManuscript (preprint) (Other academic)
  • 22.
    Jablonka, Lukas
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Solid State Electronics.
    Kubart, Thomas
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Solid State Electronics.
    Gustavsson, Fredrik
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Solid State Electronics.
    Primetzhofer, Daniel
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Applied Nuclear Physics.
    Abedin, Ahmad
    KTH Royal Institute of Technology.
    Hellström, Per-Erik
    KTH Royal Institute of Technology.
    Östling, Mikael
    KTH Royal Institute of Technology.
    Jordan-Sweet, Jean L.
    IBM, TJ Watson Research Center.
    Lavoie, Christian
    IBM, TJ Watson Research Center.
    Zhang, Shi-Li
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Solid State Electronics.
    Zhang, Zhen
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Solid State Electronics.
    Scalability Study of Nickel Germanides2016Conference paper (Refereed)
  • 23.
    Jablonka, Lukas
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Solid State Electronics.
    Kubart, Tomas
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Solid State Electronics.
    Gustavsson, Fredrik
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Solid State Electronics. Swerea KIMAB AB, Box 7047, SE-16407 Kista, Sweden.
    Descoins, Marion
    Univ Aix Marseille, CNRS, IM2NP, Case 142, F-13397 Marseille 20, France.
    Mangelinck, Dominique
    Univ Aix Marseille, CNRS, IM2NP, Case 142, F-13397 Marseille 20, France.
    Zhang, Shi-Li
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Solid State Electronics.
    Zhang, Zhen
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Solid State Electronics.
    Improving the morphological stability of nickel germanide by tantalum and tungsten additions2018In: Applied Physics Letters, ISSN 0003-6951, E-ISSN 1077-3118, Vol. 112, no 10, article id 103102Article in journal (Refereed)
    Abstract [en]

    To enhance the morphological stability of NiGe, a material of interest as a source drain-contact in Ge-based field effect transistors, Ta or W, is added as either an interlayer or a capping layer. The efficacy of this Ta or W addition is evaluated with pure NiGe as a reference. While interlayers increase the NiGe formation temperature, capping layers do not retard the NiGe formation. Regardless of the initial position of Ta or W, the morphological stability of NiGe against agglomeration can be improved by up to 100 °C. The improved thermal stability can be ascribed to an inhibited surface diffusion, owing to Ta or W being located on top of NiGe after annealing, as confirmed by means of transmission electron microscopy, Rutherford backscattering spectrometry, and atom probe tomography. The latter also shows a 0.3 €‰at. % solubility of Ta in NiGe at 450 °C, while no such incorporation of W is detectable.

  • 24.
    Jablonka, Lukas
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Solid State Electronics.
    Kubart, Tomas
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Solid State Electronics.
    Primetzhofer, Daniel
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Applied Nuclear Physics.
    Abedin, Ahmad
    KTH Royal Inst Technol, Sch Informat & Commun Technol, SE-16440 Kista, Sweden..
    Hellstrom, Per-Erik
    KTH Royal Inst Technol, Sch Informat & Commun Technol, SE-16440 Kista, Sweden..
    Ostling, Mikael
    KTH Royal Inst Technol, Sch Informat & Commun Technol, SE-16440 Kista, Sweden..
    Jordan-Sweet, Jean
    IBM Corp, TJ Watson Res Ctr, Yorktown Hts, NY 10598 USA..
    Lavoie, Christian
    IBM Corp, TJ Watson Res Ctr, Yorktown Hts, NY 10598 USA..
    Zhang, Shi-Li
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Solid State Electronics.
    Zhang, Zhen
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Solid State Electronics.
    Formation of nickel germanides from Ni layers with thickness below 10 nm2017In: Journal of Vacuum Science & Technology B, ISSN 1071-1023, E-ISSN 1520-8567, Vol. 35, no 2, article id 020602Article in journal (Refereed)
    Abstract [en]

    The authors have studied the reaction between a Ge (100) substrate and thin layers of Ni ranging from 2 to 10 nm in thickness. The formation of metal-rich Ni5Ge3 was found to precede that of the monogermanide NiGe by means of real-time in situ x-ray diffraction during ramp-annealing and ex situ x-ray pole figure analyses for phase identification. The observed sequential growth of Ni5Ge3 and NiGe with such thin Ni layers is different from the previously reported simultaneous growth with thicker Ni layers. The phase transformation from Ni5Ge3 to NiGe was found to be nucleationcontrolled for Ni thicknesses < 5 nm, which is well supported by thermodynamic considerations. Specifically, the temperature for the NiGe formation increased with decreasing Ni (rather Ni5Ge3) thickness below 5 nm. In combination with sheet resistance measurement and microscopic surface inspection of samples annealed with a standard rapid thermal processing, the temperature range for achieving morphologically stable NiGe layers was identified for this standard annealing process. As expected, it was found to be strongly dependent on the initial Ni thickness.

  • 25.
    Jablonka, Lukas
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Solid State Electronics.
    Moskovkin, Pavel
    Laboratoire d'Analyse par Réactions Nucléaires (LARN), Namur Institute of Structured Matter (NISM), University of Namur (UNamur), Namur, Belgium.
    Zhang, Zhen
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Solid State Electronics.
    Zhang, Shi-Li
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Solid State Electronics.
    Lucas, Stéphane
    Laboratoire d'Analyse par Réactions Nucléaires (LARN), Namur Institute of Structured Matter (NISM), University of Namur (UNamur), Namur, Belgium.
    Kubart, Tomas
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Solid State Electronics.
    Metal Filling by High Power Impulse Magnetron Sputtering2019In: Journal of Physics D: Applied Physics, ISSN 0022-3727, E-ISSN 1361-6463, Vol. 52, no 36, article id 365202Article in journal (Refereed)
    Abstract [en]

    High power impulse magnetron sputtering (HiPIMS) is an emerging thin film deposition technology that provides a highly ionized flux of sputtered species. This makes HiPIMS attractive for metal filling of nanosized holes for highly scaled semiconductor devices. In this work, HiPIMS filling with Cu and Co is investigated. We show that the quality of the hole filling is determined mainly by the fraction of ions in the deposited flux and their energy. The discharge waveforms alone are insufficient to determine the ionization of the metal flux. The experimental results are in a good agreement with Monte-Carlo simulations using the measured flux characteristics. Based on the simulations, strategies to improve the filling are discussed.

  • 26.
    Jablonka, Lukas
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Solid State Electronics.
    Riekehr, Lars
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Solid State Electronics.
    Zhang, Zhen
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Solid State Electronics.
    Zhang, Shi-Li
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Solid State Electronics.
    Kubart, Tomas
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Solid State Electronics.
    Highly conductive ultrathin Co films by high-power impulse magnetron sputtering2018In: Applied Physics Letters, ISSN 0003-6951, E-ISSN 1077-3118, Vol. 112, no 4, article id 043103Article in journal (Refereed)
    Abstract [en]

    Ultrathin Co films deposited on SiO2 with conductivities exceeding that of Cu are demonstrated. Ionized deposition implemented by high-power impulse magnetron sputtering (HiPIMS) is shown to result in smooth films with large grains and low resistivities, namely, 14 mu Omega cm at a thickness of 40 nm, which is close to the bulk value of Co. Even at a thickness of only 6 nm, a resistivity of 35 mu Omega cm is obtained. The improved film quality is attributed to a higher nucleation density in the Co-ion dominated plasma in HiPIMS. In particular, the pulsed nature of the Co flux as well as shallow ion implantation of Co into SiO2 can increase the nucleation density. Adatom diffusion is further enhanced in the ionized process, resulting in a dense microstructure. These results are in contrast to Co deposited by conventional direct current magnetron sputtering where the conductivity is reduced due to smaller grains, voids, rougher interfaces, and Ar incorporation. The resistivity of the HiPIMS films is shown to be in accordance with models by Mayadas-Shatzkes and Sondheimer which consider grain-boundary and surface-scattering.

  • 27. Kellock, A.
    et al.
    Lavoie, C.
    Ozcan, A.
    Rossnagel, S.
    Yang, B.
    Zhu, Y.
    Zollner, S.
    Zhen, Zhang
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Solid State Electronics.
    SILICIDE CONTACT FORMATION2010Patent (Other (popular science, discussion, etc.))
  • 28. Khater, M.
    et al.
    Lavoie, C.
    Yang, B.
    Zhen, Zhang
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Solid State Electronics.
    METHOD FOR FORMING AN SOI SCHOTTKY SOURCE/DRAIN DEVICE TO CONTROL ENCROACHMENT AND DELAMINATION OF SILICIDE2010Patent (Other (popular science, discussion, etc.))
  • 29. Khater, M
    et al.
    Lavoie, C.
    Yang, B.
    Zhen, Zhang
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Solid State Electronics.
    SOI SCHOTTKY SOURCE/DRAIN DEVICE STRUCTURE TO CONTROL ENCROACHMENT AND DELAMINATION OF SILICIDE2010Patent (Other (popular science, discussion, etc.))
  • 30. Khater, M.
    et al.
    Lavoie, C.
    Yang, B.
    Zhen, Zhang
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Solid State Electronics.
    USE EPITAXIAL NI SILICIDE2010Patent (Other (popular science, discussion, etc.))
  • 31. Khater, M.
    et al.
    Zhen, Zhang
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Solid State Electronics.
    Cai, J.
    Lavoie, C.
    D'emic, C.
    Yang, B.
    Yang, Q.
    Guillorn, M.
    Klaus, D.
    Ott, J.
    Zhu, Y.
    Choi, C.
    Frank, M.
    Lee, K.
    Narayanan, V.
    Park, D.
    Ouyang, C.
    Haensch, W.
    High-κ/Metal-Gate Fully Depleted SOI CMOS With Single-Silicide Schottky Source/Drain With Sub-30-nm Gate Length2010In: IEEE Electron Device Letters, ISSN 0741-3106, E-ISSN 1558-0563, Vol. 31, p. 275-277Article in journal (Refereed)
  • 32.
    Kubart, Tomas
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Solid State Electronics.
    Jablonka, Lukas
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Solid State Electronics.
    Zhang, Zhen
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Solid State Electronics.
    Zhang, Shi-Li
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Solid State Electronics.
    Metallization of nanostructures by High Power Impulse Magnetron Sputtering2015In: 4 th Magnetron, Ion processing & Arc Technologies European Conference, Paris, 8-11 December 2015, 2015Conference paper (Other academic)
    Abstract [en]

    In this contribution, we present the use of High Power Impulse Magnetron Sputtering (HiPIMS) for metallization of nanostructures for microelectronics. This work is motivated by meeting the increasing demands on deposition processes due to the increasing density of integration. Shrinking lateral dimensions of the structures more rapidly than vertical dimensions means increasing aspect ratios. There is also a need for deposition of new materials. Traditionally, ionized PVD (I-PVD) has been used for metallization of nanostructures. Unlike most other I-PVD techniques, HiPIMS is compatible with standard magnetron sputtering systems. It may therefore be an attractive alternative to the techniques with additional ionization of the sputtered metal flux. With two examples, we will show the great flexibility of HiPIMS in making conformal deposition vs. directed via filling.

    First, we show conformal formation of ultrathin Ni films in a modified self-aligned silicide process, thanks to the Ni ionization in HiPIMS. After appropriate annealing, the thickness of the resulting Ni-silicide films could be readily adjusted in the range from 4.7 to 8.6 nm by proper substrate biasing [1]. Good sidewall coverage was also achieved [2].

    Second, we discuss filling of via holes for vertical stacking at device level. Here, narrow (sub 100 nm) trenches and holes need to be filled with a highly conductive metal. We explore the potential of HiPIMS and determine the maximum aspect ratio that can be filled. In our experiment with Cu, the ionized metal flux fraction is estimated to be about 70% from the substrate from the substrate ion current. A significant improvement over DC sputtering has been achieved, as shown in Fig. 1, with success in filling vias of aspect ratio 1.5. We analyze the influence of ion energy and discuss approaches to further improving the filling process.

  • 33. Lavoie, C.
    et al.
    Ning, T.
    Ozcan, A.
    Yang, B.
    Zhen, Zhang
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Solid State Electronics.
    METAL-SEMICONDUCTOR INTERMIXED REGIONS2011Patent (Other (popular science, discussion, etc.))
  • 34. Lavoie, C.
    et al.
    Ozcan, A.
    Yang, B.
    Zhen, Zhang
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Solid State Electronics.
    METHOD TO CONTROL METAL SEMICONDUCTOR MICRO-STRUCTURE2010Patent (Other (popular science, discussion, etc.))
  • 35.
    Li, Shiyu
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences. Uppsala University.
    Zeng, Shuangshuang
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences.
    Chen, Lei
    Uppsala University, Disciplinary Domain of Medicine and Pharmacy, Faculty of Medicine, Department of Immunology, Genetics and Pathology.
    Zhang, Zhen
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Electrical Engineering, Solid-State Electronics.
    Hjort, Klas
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Microsystems Technology.
    Zhang, Shi-Li
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences.
    Nanoarrays on Passivated Aluminum Surface for Site-Specific Immobilization of Biomolecules2018In: ACS Applied Bio Materials, ISSN 2576-6422, Vol. 1, no 1, p. 125-135Article in journal (Refereed)
    Abstract [en]

    The rapid development of biosensing platforms for highly sensitive and specific detection raises the desire of precise localization of biomolecules onto various material surfaces. Aluminum has been strategically employed in the biosensor system due to its compatibility with CMOS technology and its optical and electrical properties such as prominent propagation of surface plasmons. Herein, we present an adaptable method for preparation of carbon nanoarrays on aluminum surface passivated with poly(vinylphosphonic acid) (PVPA). The carbon nanoarrays were defined by means of electron beam induced deposition (EBID) and they were employed to realize site-specific immobilization of target biomolecules. To demonstrate the concept, selective streptavidin/neutravidin immobilization on the carbon nanoarrays was achieved through protein physisorption with a significantly high contrast of the carbon domains over the surrounding PVPA-modified aluminum surface. By adjusting the fabrication parameters, local protein densities could be varied on similarly sized nanodomains in a parallel process. Moreover, localization of single 40 nm biotinylated beads was achieved by loading them on the neutravidin-decorated nanoarrays. As a further demonstration, DNA polymerase with a streptavidin tag was bound to the biotin-beads that were immobilized on the nanoarrays and in situ rolling circle amplification (RCA) was subsequently performed. The observation of organized DNA arrays synthesized by RCA verified the nanoscale localization of the enzyme with retained biological activity. Hence, the presented approach could provide a flexible and universal avenue to precise localizing various biomolecules on aluminum surface for potential biosensor and bioelectronic applications. 

  • 36. Liu, F.
    et al.
    Fletcher, B.
    Joseph, E.
    Zhu, Y.
    Gonsalves, J.
    Price, W.
    Fritz, G.
    Engelmann, S.
    Pyzyna, A.
    Zhen, Zhang
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Solid State Electronics.
    Cabral, C.
    Guillorn, M.
    Subtractive W Contact and Local Interconnect Co-integration (CLIC)2013Conference paper (Refereed)
  • 37. Luo, J.
    et al.
    Qiu, Z.
    Zha, C.
    Zhen, Zhang
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Solid State Electronics.
    Wu, D.
    Lu, J.
    Akerman, J.
    Ostling, M.
    Hultman, L.
    Zhang, Shi-Li
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Solid State Electronics.
    Surface-energy triggered phase formation and epitaxy in nanometer-thick Ni1−xPtx silicide films2010In: Applied Physics Letters, ISSN 0003-6951, E-ISSN 1077-3118, Vol. 96, p. 071915-Article in journal (Refereed)
  • 38. Luo, J
    et al.
    Qiu, Z.
    Zhen, Zhang
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Solid State Electronics.
    Ostling, M.
    Zhang, Shi-Li
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Solid State Electronics.
    Interaction of NiSi with dopants for metallic source/drain applications2010In: Journal of Vacuum Science & Technology B, ISSN 1071-1023, E-ISSN 1520-8567, Vol. 28, p. 1071-Article in journal (Refereed)
  • 39.
    Luo, Jun
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Applied Materials Sciences.
    Qiu, Zhi-Jun
    Zhang, Zhen
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Solid State Electronics.
    Östling, Mikael
    Zhang, Shi-Li
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Solid State Electronics.
    Interaction of NiSi with dopants for metallic source/drain applications2010In: Journal of Vacuum Science & Technology B, ISSN 1071-1023, E-ISSN 1520-8567, Vol. 28, no 1, p. C1I1-C1I11Article in journal (Refereed)
    Abstract [en]

    This work has a focus on NiSi as a possible metallic contact for aggressively scaled complementary metal oxide semiconductor devices. As the bulk work function of NiSi lies close to the middle of Si bandgap, the Schottky barrier height (SBH) of NiSi is rather large for both electron ( ∼ 0.65 eV) and hole ( ∼ 0.45 eV). Different approaches have therefore been intensively investigated in the literature aiming at reducing the effective SBH: dopant segregation (DS), surface passivation (SP), and alloying, in order to improve the carrier injection into the conduction channel of a field-effect transistor. The present work explores DS using B and As for the NiSi/Si contact system. The effects of C and N implantation into Si substrate prior to the NiSi formation are examined, and it is found that the presence of C yields positive effects in helping reduce the effective SBH to 0.1–0.2 eV for both conduction polarities. A combined use of DS or SP with alloying could be considered for more effective control of effective SBH, but an examination of undesired compound formation and its probable consequences is necessary. Furthermore, an analysis of the metal silicides that have a small “intrinsic” SBH reveals that only a very small number of them are of practical interest as most of the silicides require either a high formation temperature or possess a high specific resistivity.

  • 40. Luo, Jun
    et al.
    Zhijun, Qiu
    Chaolin, Zha
    Zhen, Zhang
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Solid State Electronics.
    Dongping, Wu
    Jun, Lu
    Johan, Akerman
    Mikael, Ostling
    Lars, Hultman
    Shi-Li, Zhang
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Solid State Electronics.
    Surface-energy triggered phase formation and epitaxy in nanometer-thick Ni1−xPtx silicide films2010In: Applied Physics Letters, ISSN 0003-6951, E-ISSN 1077-3118, Vol. 96, no 3, p. 031911-Article in journal (Refereed)
    Abstract [en]

    The formation of ultrathin silicide films of Ni1−xPtx at 450–850 °C is reported. Without Pt (x=0) and for tNi<4 nm, epitaxially aligned NiSi2−y films readily grow and exhibit extraordinary morphological stability up to 800 °C. For tNi≥4 nm, polycrystalline NiSi films form and agglomerate at lower temperatures for thinner films. Without Ni (x=1) and for tPt=1–20 nm, the annealing behavior of the resulting PtSi films follows that for the NiSi films. The results for Ni1−xPtx of other compositions support the above observations. Surface energy is discussed as the cause responsible for the distinct behavior in phase formation and morphological stability.

  • 41.
    Makaraviciute, Asta
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Solid State Electronics.
    Xu, Xingxing
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Solid State Electronics.
    Nyholm, Leif
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström, Inorganic Chemistry.
    Zhang, Zhen
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Solid State Electronics.
    Systematic approach to the development of microfabricated biosensors: relationship between the gold surface pretreatment and thiolated molecule binding2017In: ACS Applied Materials and Interfaces, ISSN 1944-8244, E-ISSN 1944-8252, Vol. 9, no 31, p. 26610-26621Article in journal (Refereed)
    Abstract [en]

    Despite the increasing popularity of microfabricated biosensors due to advances in technologic and surface functionalization strategies, their successful implementation is partially inhibited by the lack of consistency in their analytical characteristics. One of the main causes for the discrepancies is the absence of a systematic and comprehensive approach to surface functionalization. In this article microfabricated gold electrodes aimed at biosensor development have been systematically characterized in terms of surface pretreatment, thiolated molecule binding, and reproducibility by means of X-ray photoelectron scattering (XPS) and cyclic voltammetry (CV). It has been shown that after SU-8 photolithography gold surfaces were markedly contaminated, which decreased the effective surface area and surface coverage of a model molecule mercaptohexanol (MCH). Three surface pretreatment methods compatible with microfabricated devices were compared. The investigated methods were (i) cyclic voltammetry in dilute H2SO4, (ii) gentle basic piranha followed by linear sweep voltammetry in dilute KOH, and (iii) oxygen plasma treatment followed by incubation in ethanol. It was shown that all three methods significantly decreased the contamination and increased MCH surface coverage. Most importantly, it was also revealed that surface pretreatments may induce structural changes to the gold surfaces. Accordingly, these alterations influence the characteristics of MCH functionalization.

  • 42.
    Netzer, Nathan L.
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Solid State Electronics.
    Must, Indrek
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Solid State Electronics.
    Qiao, Yupu
    Univ South Dakota, Dept Chem, 414 E Clark St, Vermillion, SD 57069 USA..
    Zhang, Shi-Li
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Solid State Electronics.
    Wang, Zhenqiang
    Univ South Dakota, Dept Chem, 414 E Clark St, Vermillion, SD 57069 USA..
    Zhang, Zhen
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Solid State Electronics.
    Biomimetic supercontainers for size-selective electrochemical sensing of molecular ions2017In: Scientific Reports, ISSN 2045-2322, E-ISSN 2045-2322, Vol. 7, article id 45786Article in journal (Refereed)
    Abstract [en]

    New ionophores are essential for advancing the art of selective ion sensing. Metal-organic supercontainers (MOSCs), a new family of biomimetic coordination capsules designed using sulfonylcalix[4] arenes as container precursors, are known for their tunable molecular recognition capabilities towards an array of guests. Herein, we demonstrate the use of MOSCs as a new class of size-selective ionophores dedicated to electrochemical sensing of molecular ions. Specifically, a MOSC molecule with its cavities matching the size of methylene blue (MB+), a versatile organic molecule used for bio-recognition, was incorporated into a polymeric mixed-matrix membrane and used as an ion-selective electrode. This MOSC-incorporated electrode showed a near-Nernstian potentiometric response to MB+ in the nano-to micro-molar range. The exceptional size-selectivity was also evident through contrast studies. To demonstrate the practical utility of our approach, a simulated wastewater experiment was conducted using water from the Fyris River (Sweden). It not only showed a near-Nernstian response to MB+ but also revealed a possible method for potentiometric titration of the redox indicator. Our study thus represents a new paradigm for the rational design of ionophores that can rapidly and precisely monitor molecular ions relevant to environmental, biomedical, and other related areas.

  • 43. Raymond, M
    et al.
    Yang, B.
    Zhen, Zhang
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Solid State Electronics.
    Ozcan, A.
    Lavoie, C.
    Silicide Contact Resistivity and Phase Formation for Extremely Scaled CMOS Device Applications2012Conference paper (Refereed)
  • 44.
    Tran, Tuan
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Applied Nuclear Physics.
    Jablonka, Lukas
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Solid State Electronics.
    Bruckner, Barbara
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Applied Nuclear Physics. Johannes Kepler Univ Linz, Atom Phys & Surface, A-4040 Linz, Austria.
    Rund, Stefanie
    Johannes Kepler Univ Linz, Atom Phys & Surface, A-4040 Linz, Austria.
    Roth, Dietmar
    Johannes Kepler Univ Linz, Atom Phys & Surface, A-4040 Linz, Austria.
    Sortica, Mauricio A.
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Applied Nuclear Physics.
    Bauer, Peter
    Uppsala University, Disciplinary Domain of Science and Technology, För teknisk-naturvetenskapliga fakulteten gemensamma enheter, Tandem Laboratory. Johannes Kepler Univ Linz, Atom Phys & Surface, A-4040 Linz, Austria.
    Zhang, Zhen
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Solid State Electronics.
    Primetzhofer, Daniel
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Applied Nuclear Physics.
    Electronic interaction of slow hydrogen and helium ions with nickel-silicon systems2019In: Physical Review A: covering atomic, molecular, and optical physics and quantum information, ISSN 2469-9926, E-ISSN 2469-9934, Vol. 100, no 3, article id 032705Article in journal (Refereed)
    Abstract [en]

    Electronic stopping cross sections (SCSs) of nickel, silicon, and nickel-silicon alloys for protons and helium (He) ions are studied in the regime of medium- and low-energy ion scattering, i.e., for ion energies in the range from 500 eV to 200 keV. For protons, at velocities below the Bohr velocity the deduced SCS is proportional to the ion velocity for all investigated materials. In contrast, for He ions nonlinear velocity scaling is observed in all investigated materials. Static calculations using density functional theory (DFT) available from the literature accurately predict the SCS of Ni and Ni-Si alloy in the regime with observed velocity proportionality. At higher energies, the energy dependence of the deduced SCS of Ni for protons and He ions agrees with the prediction by recent time-dependent DFT calculations. The measured SCS of the Ni-Si alloy was compared to the SCS obtained from Bragg's rule based on SCS for Ni and Si deduced in this study, yielding good agreement for protons, but systematic deviations for He projectiles, by almost 20%. Overall, the obtained data indicate the importance of nonadiabatic processes such as charge exchange for proper modeling of electronic stopping of, in particular, medium-energy ions heavier than protons in solids.

  • 45.
    Tseng, Chiao-Wei
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Solid State Electronics.
    Wen, Chenyu
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Solid State Electronics.
    Huang, Ding-Chi
    Institute of Chemistry, Academia Sinica, Taiwan.
    Lai, Chin-Hung
    Department of Medical Applied Chemistry, Chung Shan Medical University, Taiwan.
    Chen, Si
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Solid State Electronics.
    Hu, Qitao
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Solid State Electronics.
    Chen, Xi
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Solid State Electronics.
    Xu, Xingxing
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Solid State Electronics.
    Zhang, Shi-Li
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Solid State Electronics.
    Tao, Yu-Tai
    Institute of Chemistry, Academia Sinica, Taiwan.
    Zhang, Zhen
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Solid State Electronics.
    Synergy of Ionic and Dipolar Effects by Molecular Designfor pH Sensing beyond the Nernstian Limit2019In: Advanced Science, ISSN 2198-3844Article in journal (Refereed)
  • 46.
    Wen, Chenyu
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Solid State Electronics.
    Li, Shiyu
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Solid State Electronics.
    Zeng, Shuangshuang
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Solid State Electronics.
    Zhang, Zhen
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Solid State Electronics.
    Zhang, Shi-Li
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Solid State Electronics.
    Autogenic analyte translocation in nanopores2019In: Nano Energy, ISSN 2211-2855, E-ISSN 2211-3282, Vol. 60, p. 503-509Article in journal (Refereed)
    Abstract [en]

    Nanopores have been widely studied for power generation and single-molecule detection. Although the power level generated by a single nanopore based on electrolyte concentration gradient is too low to be practically useful, such a power level is found sufficient to drive analyte translocation in nanopores. Here, we explore the simultaneous action of a solid-state nanopore as a nanopower generator and a nanoscale biosensor by exploiting the extremely small power generated to drive the analyte translocation in the same nanopore device. This autogenic analyte translocation is demonstrated using protein and DNA for their distinct shape, size and charge. The simple device structure allows for easy implementation of either electrical or optical readout. The obtained nanopore translocation is characterized by typical behaviors expected for an ordinary nanopore sensor powered by an external source. Extensive numerical simulation confirms the power generation and power level generated. It also reveals the fundamentals of autogenic translocation. As it requires no external power source, the sensing can be conducted with simple readout electronics and may allow for integration of high-density nanopores. Our approach demonstrated in this work may pave the way to practical high-throughput single-molecule nanopore sensing powered by the distributed energy harvested by the nanopores themselves.

  • 47.
    Wen, Chenyu
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Solid State Electronics.
    Zeng, Shuangshuang
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Solid State Electronics.
    Arstila, Kai
    Department of Physics, University of Jyväskylä, Jyvaskylä, Finland.
    Sajavaara, Timo
    Department of Physics, University of Jyväskylä, Jyvaskylä, Finland.
    Zhu, Yu
    IBM Thomas J. Watson Research Center, New York, United States.
    Zhang, Zhen
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Solid State Electronics.
    Zhang, Shi-Li
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Solid State Electronics.
    Generalized Noise Study of Solid-State Nanopores at Low Frequencies2017In: ACS Sensors, ISSN 2379-3694, Vol. 2, no 2, p. 300-307Article in journal (Refereed)
    Abstract [en]

    Nanopore technology has been extensively investigated for analysis of biomolecules, and a success story in this field concerns DNA sequencing using a nanopore chip featuring an array of hundreds of biological nanopores (BioNs). Solid-state nanopores (SSNs) have been explored to attain longer lifetime and higher integration density than what BioNs can offer, but SSNs are generally considered to generate higher noise whose origin remains to be confirmed. Here, we systematically study lowfrequency (including thermal and flicker) noise characteristics of SSNs measuring 7 to 200 nm in diameter drilled through a 20-nmthick SiNx membrane by focused ion milling. Both bulk and surface ionic currents in the nanopore are found to contribute to the flicker noise, with their respective contributions determined by salt concentration and pH in electrolytes as well as bias conditions. Increasing salt concentration at constant pH and voltage bias leads to increase in the bulk ionic current and noise therefrom. Changing pH at constant salt concentration and current bias results in variation of surface charge density, and hence alteration of surface ionic current and noise. In addition, the noise from Ag/AgCl electrodes can become predominant when the pore size is large and/or the salt concentration is high. Analysis of our comprehensive experimental results leads to the establishment of a generalized nanopore noise model. The model not only gives an excellent account of the experimental observations, but can also be used for evaluation of various noise components in much smaller nanopores currently not experimentally available.

  • 48.
    Wen, Chenyu
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Solid State Electronics.
    Zeng, Shuangshuang
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Solid State Electronics.
    Li, Shiyu
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Solid State Electronics.
    Zhang, Zhen
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Solid State Electronics.
    Zhang, Shi-Li
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Solid State Electronics.
    On rectification of ionic current in nanopores2019In: Analytical Chemistry, ISSN 0003-2700, E-ISSN 1520-6882, Vol. 91, no 22, p. 14597-14604Article in journal (Refereed)
  • 49.
    Wen, Chenyu
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Solid State Electronics.
    Zeng, Shuangshuang
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Solid State Electronics.
    Li, Shiyu
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Solid State Electronics.
    Zhang, Zhen
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Solid State Electronics.
    Zhang, Shi-Li
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Solid State Electronics.
    Translocation properties of analytes through asymmetric nanopores2019Conference paper (Refereed)
  • 50.
    Wen, Chenyu
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Solid State Electronics. Uppsala University.
    Zeng, Shuangshuang
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Solid State Electronics.
    Zhang, Zhen
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Solid State Electronics.
    Hjort, Klas
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Microsystems Technology.
    Scheicher, Ralph
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy.
    Zhang, Shi-Li
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Solid State Electronics.
    On nanopore DNA sequencing by signal and noise analysis of ionic current2016In: Nanotechnology, ISSN 0957-4484, E-ISSN 1361-6528, Vol. 27, article id 215502Article in journal (Refereed)
    Abstract [en]

    DNA sequencing, i.e., the process of determining the succession of nucleotides on a DNA strand, has become a standard aid in biomedical research and is expected to revolutionize medicine. With the capability of handling single DNA molecules, nanopore technology holds high promises to become speedier in sequencing at lower cost than what are achievable with the commercially available optics-or semiconductor-based massively parallelized technologies. Despite tremendous progress made with biological and solid-state nanopores, high error rates and large uncertainties persist with the sequencing results. Here, we employ a nano-disk model to quantitatively analyze the sequencing process by examining the variations of ionic current when a DNA strand translocates a nanopore. Our focus is placed on signal-boosting and noise-suppressing strategies in order to attain the single-nucleotide resolution. Apart from decreasing pore diameter and thickness, it is crucial to also reduce the translocation speed and facilitate a stepwise translocation. Our best-case scenario analysis points to severe challenges with employing plain nanopore technology, i.e., without recourse to any signal amplification strategy, in achieving sequencing with the desired single-nucleotide resolution. A conceptual approach based on strand synthesis in the nanopore of the translocating DNA from single-stranded to double-stranded is shown to yield a 10-fold signal amplification. Although it involves no advanced physics and is very simple in mathematics, this simple model captures the essence of nanopore sequencing and is useful in guiding the design and operation of nanopore sequencing.

123 1 - 50 of 110
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