Change search
CiteExportLink to record
Permanent link

Direct link
Cite
Citation style
  • apa
  • ieee
  • modern-language-association-8th-edition
  • vancouver
  • Other style
More styles
Language
  • de-DE
  • en-GB
  • en-US
  • fi-FI
  • nn-NO
  • nn-NB
  • sv-SE
  • Other locale
More languages
Output format
  • html
  • text
  • asciidoc
  • rtf
Experimental Studies of Charge Transport in Single Crystal Diamond Devices
Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Electricity. (Department of Engineering Sciences, Electricity (Diamond electronics)))
2012 (English)Doctoral thesis, comprehensive summary (Other academic)
Abstract [en]

Diamond is a promising material for high-power, high-frequency and high- temperature electronics applications, where its outstanding physical properties can be fully exploited. It exhibits an extremely high bandgap, very high carrier mobilities, high breakdown field strength, and the highest thermal conductivity of any wide bandgap material. It is therefore an outstanding candidate for the fastest switching, the highest power density, and the most efficient electronic devices obtainable, with applications in the RF power, automotive and aerospace industries. Lightweight diamond devices, capable of high temperature operation in harsh environments, could also be used in radiation detectors and particle physics applications where no other semiconductor devices would survive.

The high defect and impurity concentration in natural diamond or high-pressure-high-temperature (HPHT) diamond substrates has made it difficult to obtain reliable results when studying the electronic properties of diamond. However, progress in the growth of high purity Single Crystal Chemical Vapor Deposited (SC-CVD) diamond has opened the perspective of applications under such extreme conditions based on this type of synthetic diamond.

Despite the improvements, there are still many open questions. This work will focus on the electrical characterization of SC-CVD diamond by different measurement techniques such as internal photo-emission, I-V, C-V, Hall measurements and in particular, Time-of-Flight (ToF) carrier drift velocity measurements. With these mentioned techniques, some important properties of diamond such as drift mobilities, lateral carrier transit velocities, compensation ratio and Schottky barrier heights have been investigated. Low compensation ratios (ND/NA) < 10-4 have been achieved in boron-doped diamond and a drift mobility of about 860 cm2/Vs for the hole transit near the surface in a lateral ToF configuration could be measured. The carrier drift velocity was studied for electrons and holes at the temperature interval of 80-460 K. The study is performed in the low-injection regime and includes low-field drift mobilities. The hole mobility was further investigated at low temperatures (10-80 K) and as expected a very high mobility was observed.

In the case of electrons, a negative differential mobility was seen in the temperature interval of 100-150K. An explanation for this phenomenon is given by the intervally scattering and the relation between hot and cold conduction band valleys. This was observed in direct bandgap semiconductors with non-equivalent valleys such as GaAs but has not been seen in diamond before.

Furthermore, first steps have been taken to utilize diamond for infrared (IR) radiation detection. To understand the fundamentals of the thermal response of diamond, Temperature Coefficient of Resistance (TCR) measurements were performed on diamond Schottky diodes which are a candidate for high temperature sensors. As a result, very high TCR values in combination with a low noise constant (K1/f) was observed.

Place, publisher, year, edition, pages
Uppsala: Acta Universitatis Upsaliensis, 2012. , 67 p.
Series
Digital Comprehensive Summaries of Uppsala Dissertations from the Faculty of Science and Technology, ISSN 1651-6214 ; 944
Keyword [en]
Single crystal diamond, carrier transport, CVD diamond, time-of-flight, mobility, IR detector, compensation, diamond diode, drift velocity, thermal detector
National Category
Engineering and Technology
Identifiers
URN: urn:nbn:se:uu:diva-173599ISBN: 978-91-554-8391-3 (print)OAI: oai:DiVA.org:uu-173599DiVA: diva2:524559
Public defence
2012-06-05, Häggsalen, Lägerhyddsvägen 1, Ångströmlaboratoriet, Uppsala, 13:15 (English)
Opponent
Supervisors
Available from: 2012-05-15 Created: 2012-05-01 Last updated: 2013-01-07Bibliographically approved
List of papers
1. Compensation in boron-doped CVD diamond
Open this publication in new window or tab >>Compensation in boron-doped CVD diamond
Show others...
2008 (English)In: Physica status solidi. A, Applications and Materials Science, ISSN 1862-6300, Vol. 205, no 9, 2190-2194 p.Article in journal (Refereed) Published
Abstract [en]

Hall-effect measurements on single crystal boron-doped CVD diamond in the temperature interval 80-450 K are presented together with SIMS measurements of the dopant concentration. Capacitance-voltage measurements on rectifying Schottky junctions manufactured on the boron-doped structures are also presented in this context. Evaluation of the compensating donor (N-D) and acceptor concentrations (N-A) show that in certain samples very low compensation ratios (N-D/N-A below 10(-4)) have been achieved. The influence of compensating donors on majority carrier transport and the significance for diamond device performance are briefly discussed.

National Category
Materials Engineering Engineering and Technology
Identifiers
urn:nbn:se:uu:diva-107876 (URN)10.1002/pssa.200879711 (DOI)000259653700017 ()
Available from: 2009-08-31 Created: 2009-08-31 Last updated: 2017-01-25
2. Characterization by Internal Photoemission Spectroscopy of Single-Crystal CVD Diamond Schottky Barrier Diodes
Open this publication in new window or tab >>Characterization by Internal Photoemission Spectroscopy of Single-Crystal CVD Diamond Schottky Barrier Diodes
Show others...
2010 (English)In: Journal of Electronic Materials, ISSN 0361-5235, E-ISSN 1543-186X, Vol. 39, no 8, 1203-1208 p.Article in journal (Refereed) Published
Abstract [en]

Internal photoemission spectroscopy measurements have been performed to study the electrical characteristics of Schottky diodes on boron-doped single-crystalline chemical vapor deposited (SC-CVD) diamond. These measurements were compared with current-voltage (I-V) and current-temperature (I-T) measurements. Schottky contact barrier heights and ideality factors have been measured on Schottky contacts formed on four samples with Au, Ni, and Al contact metallizations. I-V and I-T measurements were performed in the temperature range from 300 K to 500 K. The internal photoemission method, which is less influenced by local variations in the Schottky barrier height than the other two methods, yielded the highest values of Schottky barrier heights to p-type material: I broken vertical bar(B) = 1.78 eV to 2.10 eV, depending on the choice of contact metal and sample boron concentration.

Keyword
CVD diamond, Schottky barrier diodes, internal photoemission spectroscopy, Schottky barrier heights
National Category
Engineering and Technology
Identifiers
urn:nbn:se:uu:diva-135814 (URN)10.1007/s11664-010-1255-8 (DOI)000279504900012 ()
Available from: 2010-12-09 Created: 2010-12-08 Last updated: 2017-12-11Bibliographically approved
3. A lateral time-of-flight system for charge transport studies
Open this publication in new window or tab >>A lateral time-of-flight system for charge transport studies
Show others...
2009 (English)In: Diamond and related materials, ISSN 0925-9635, E-ISSN 1879-0062, Vol. 18, no 9, 1163-1166 p.Article in journal (Refereed) Published
Abstract [en]

A measurement system for lateral ToF charge carrier transport studies in intrinsic diamond is described. In the lateral ToF geometry, carriers travel close to the sample surface and the system is therefore particularly suited for studies of thin layers as well as the influence of different surface conditions on transport dynamics. A 213nm pulsed UV laser is used to create electron-hole pairs along a line focus between two parallel metal electrodes on one surface. The use of reflective UV-optics with short focal length allows for a narrow focal line and also for imaging the sample in UV or visible light without any dispersion. A clear hole transit was observed in one homoepitaxial single crystalline diamond film for which the substrate was treated by a Ar/Cl plasma etch prior to deposition. The hole transit signal was sufficiently clear to measure the near-surface hole drift mobility of about 860cm2/Vs across a contact spacing of 0.3mm.

Place, publisher, year, edition, pages
Langford Lane, Kidlington, Oxford, OX5 1GB, United Kingdom: Elsevier Ltd, 2009
Keyword
Mobility, Time-of-Flight, CVD diamond, Single crystal diamond
National Category
Engineering and Technology
Identifiers
urn:nbn:se:uu:diva-113146 (URN)10.1016/j.diamond.2009.03.002 (DOI)000268610700020 ()09259635 (ISBN)
Note

Compilation and indexing terms, Copyright 2009 Elsevier Inc. 20092812180300 Charge transport CVD diamond Electron hole pairs Focal lengths Homoepitaxial Line-focus Measurement system Metal electrodes Mobility Near-surface Plasma etch Pulsed UV-lasers Sample surface Single crystal diamond Single-crystalline diamond Surface conditions Thin layers Time-of-Flight Time-of-flight system Transport dynamics Visible light

Available from: 2010-01-25 Created: 2010-01-25 Last updated: 2017-12-12Bibliographically approved
4. Electron and hole drift velocity in chemical vapor deposition diamond
Open this publication in new window or tab >>Electron and hole drift velocity in chemical vapor deposition diamond
2011 (English)In: Journal of Applied Physics, ISSN 0021-8979, E-ISSN 1089-7550, Vol. 109, no 6, 063719- p.Article in journal (Refereed) Published
Abstract [en]

The time-of-flight technique has been used to measure the drift velocities for electrons and holes in high-purity single-crystalline CVD diamond. Measurements were made in the temperature interval 83 ≤ T ≤ 460 K and for electric fields between 90 and 4 × 103 V/cm, applied in the <100> crystallographic direction. The study includes low-field drift mobilities and is performed in the low-injection regime to perturb the applied electric field only minimally.

Keyword
velocity, time-of-flight, carrier drift mobility, single crystal diamond
National Category
Condensed Matter Physics Engineering and Technology
Research subject
Physics with spec. in Atomic, Molecular and Condensed Matter Physics; Engineering Science with specialization in Science of Electricity
Identifiers
urn:nbn:se:uu:diva-122792 (URN)10.1063/1.3554721 (DOI)000289149900072 ()
Funder
Swedish Research Council
Available from: 2011-04-09 Created: 2010-04-20 Last updated: 2017-12-12Bibliographically approved
5. Negative electron mobility in diamond
Open this publication in new window or tab >>Negative electron mobility in diamond
2012 (English)In: Applied Physics Letters, ISSN 0003-6951, E-ISSN 1077-3118, Vol. 100, no 17, 172103- p.Article in journal (Refereed) Published
Abstract [en]

By measuring the drift velocity of electrons in diamond as a function of applied electric field, wedemonstrate that ultra-pure diamond exhibits negative differential electron mobility in the [100] directionbelow 140 K. Negative electron mobility is normally associated with III–V or II–VI semiconductors withan energy difference between different conduction band valleys. The observation of negative mobility indiamond, an elemental group IV semiconductor, is explained in terms of repopulation effects betweendifferent equivalent conduction band valleys using a model based on the Boltzmann equation.

Place, publisher, year, edition, pages
American Institute of Physics (AIP), 2012
National Category
Engineering and Technology
Research subject
Engineering Science with specialization in Science of Electricity
Identifiers
urn:nbn:se:uu:diva-173582 (URN)10.1063/1.4705434 (DOI)000303340300034 ()
Available from: 2012-05-02 Created: 2012-04-29 Last updated: 2017-12-07Bibliographically approved
6. Low Temperature Hole Transport in Single Crystal Synthetic Diamond
Open this publication in new window or tab >>Low Temperature Hole Transport in Single Crystal Synthetic Diamond
2012 (English)In: Physical Review B Condensed Matter, ISSN 0163-1829, E-ISSN 1095-3795Article in journal (Refereed) Published
Abstract [en]

Hole transport properties of boron-doped single-crystalline (SC) CVD diamond, growth in the<100> crystallographic direction, has been investigated. The measurement was carried out in thetemperature range 10  T  80 K. A Time-of-Flight (ToF) measurement, using a 213 nm, pulsedultraviolet laser for excitation was performed on high-purity SC diamonds to study hole driftmobility in the low-injection regime and the scattering mechanisms involved in the process. Asaturation of the hole mobility was observed. This indicates that impurity scattering is thedominating scattering process at these low temperatures.

Keyword
ToF, time-of-flight, scattering, drift velocity, CVD diamond, single crystal diamond
National Category
Engineering and Technology
Identifiers
urn:nbn:se:uu:diva-173598 (URN)
Available from: 2012-05-02 Created: 2012-05-01 Last updated: 2017-12-07Bibliographically approved
7. High Performance Temperature Sensors using SC-CVD Diamond Schottky Diodes
Open this publication in new window or tab >>High Performance Temperature Sensors using SC-CVD Diamond Schottky Diodes
Show others...
2012 (English)In: Applied Physics Letters, ISSN 0003-6951, E-ISSN 1077-3118Article in journal, Letter (Refereed) Published
Abstract [en]

The synthesis of new materials for thermal IR detection has been an intensive research area during the recent years. Among the new materials, diamond has the ability to function under high temperature, high power, and high radiation conditions, which enables large performance enhancements to a wide variety of systems and applications, e.g. electric vehicles, space exploration and nuclear energy reactors. In this study, diamond Schottky diodes (with boron concentrations in the range 1×1015 - 3×1016 cm-3) are presented as candidates for IR sensors with an excellent temperature coefficient of resistance (-16 %/K) and noise levels around 1.8×10-14 (V2/Hz).

Keyword
CVD diamond, TCR, Schottky diodes, IR detector
National Category
Engineering and Technology
Identifiers
urn:nbn:se:uu:diva-173597 (URN)
Available from: 2012-05-02 Created: 2012-05-01 Last updated: 2017-12-07Bibliographically approved

Open Access in DiVA

fulltext(60852 kB)1734 downloads
File information
File name FULLTEXT01.pdfFile size 60852 kBChecksum SHA-512
aa8db65282b62dfe5ad71e971178bd03cbbdf91beac57cda14459d2535bfda189e5e40cf6f9656c34156d85d8f493d14f9f3ace606240ca12b287e14c66c1740
Type fulltextMimetype application/pdf
Buy this publication >>

Search in DiVA

By author/editor
Majdi, Saman
By organisation
Electricity
Engineering and Technology

Search outside of DiVA

GoogleGoogle Scholar
Total: 1734 downloads
The number of downloads is the sum of all downloads of full texts. It may include eg previous versions that are now no longer available

isbn
urn-nbn

Altmetric score

isbn
urn-nbn
Total: 984 hits
CiteExportLink to record
Permanent link

Direct link
Cite
Citation style
  • apa
  • ieee
  • modern-language-association-8th-edition
  • vancouver
  • Other style
More styles
Language
  • de-DE
  • en-GB
  • en-US
  • fi-FI
  • nn-NO
  • nn-NB
  • sv-SE
  • Other locale
More languages
Output format
  • html
  • text
  • asciidoc
  • rtf