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Design, Modelling and Characterization of Si/SiGe Structures for IR Bolometer Applications
KTH, School of Information and Communication Technology (ICT), Integrated Devices and Circuits.
2015 (English)Licentiate thesis, comprehensive summary (Other academic)
Abstract [en]

This thesis presents SiGe(C)/Si(C) multi quantum well (MQW) layers individually or in combination with Si(C) Schottky diodes as material structures to detect infrared (IR) radiation. The performance of devices was investigated in terms of SiGe/Si periodicity and quality of SiGe/Si interface. The structures were grown by chemical vapour deposition using GeH4 and SiH4 sources at 650 °C and processed into pixel arrays with sizes of 25×25, 100×100 and 200×200 μm2. The device response to thermal variations was expressed by temperature coefficient of resistance (TCR) and the signal-to-noise-ratio was evaluated by noise measurements. The strain relaxation in SiGe layers was investigated by implementing oxygen at the interface of SiGe/Si or during SiGe growth. A minor amount of 10 ppb oxygen at the interface can be detected by noise measurements while the material characterizations could reveal defects for significantly higher defect density. Oxygen and water contaminations should be accounted for in low temperature epitaxy (350-650 °C) of the layers. Furthermore, an empirical model was developed to describe the kinetics of the SiGe growth using Si2H6 and Ge2H6 as precursors at low temperature. The model takes into account the energy for dissociation of gas molecules, diffusion of the molecules from the gas boundaries toward the substrate and the incorporation of absorbed molecules. A good consistency was observed between the experimental and calculated data.

Place, publisher, year, edition, pages
Stockholm: KTH Royal Institute of Technology, 2015. , xv, 48 p.
TRITA-ICT/MAP AVH, ISSN 1653-7610 ; 2015:01
National Category
Nano Technology
URN: urn:nbn:se:kth:diva-159762ISBN: 978-91-7595-422-6 (print)OAI: diva2:787350
2015-02-12, Sal/Hall A, KTH- Electrum, Kista, Stockholm, 10:00 (English)

QC 20150211

Available from: 2015-02-11 Created: 2015-02-10 Last updated: 2015-02-11Bibliographically approved
List of papers
1. Characterization of SiGe/Si multi-quantum wells for infrared sensing
Open this publication in new window or tab >>Characterization of SiGe/Si multi-quantum wells for infrared sensing
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2013 (English)In: Applied Physics Letters, ISSN 0003-6951, E-ISSN 1077-3118, Vol. 103, no 25, 251609- p.Article in journal (Refereed) Published
Abstract [en]

SiGe epitaxial layers are integrated as an active part in thermal detectors. To improve their performance, deeper understanding of design parameters, such as thickness, well periodicity, quality, and strain amount, of the layers/interfaces is required. Oxygen (2-2500 × 10-9 Torr) was exposed prior or during epitaxy of SiGe/Si multilayers. In this range, samples with 10 nTorr oxygen were processed to investigate layer quality and noise measurements. Temperature coefficient of resistance was also measured to evaluate the thermal response. These results demonstrate sensitivity of SiGe-based devices to size and location of defects in the structure.

Thin-Films, Temperature, Bolometers, Pressure, Epitaxy
National Category
Other Physics Topics
urn:nbn:se:kth:diva-140927 (URN)10.1063/1.4855595 (DOI)000329973800025 ()2-s2.0-84891448173 (Scopus ID)
EU, European Research Council

QC 20140204

Available from: 2014-02-04 Created: 2014-02-04 Last updated: 2017-12-06Bibliographically approved
2. Enhanced device designs for Si-based infrared detectors
Open this publication in new window or tab >>Enhanced device designs for Si-based infrared detectors
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2015 (English)In: Applied Physics Letters, ISSN 0003-6951, E-ISSN 1077-3118Article in journal (Other academic) Submitted
National Category
Nano Technology
urn:nbn:se:kth:diva-159760 (URN)

QS 2015

Available from: 2015-02-10 Created: 2015-02-10 Last updated: 2017-12-04Bibliographically approved
3. Kinetic Modeling of Low Temperature Epitaxy Growth of SiGe Using Disilane and Digermane
Open this publication in new window or tab >>Kinetic Modeling of Low Temperature Epitaxy Growth of SiGe Using Disilane and Digermane
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2012 (English)In: Journal of the Electrochemical Society, ISSN 0013-4651, E-ISSN 1945-7111, Vol. 159, no 5, H478-H481 p.Article in journal (Refereed) Published
Abstract [en]

Low temperature epitaxy (LTE) in Chemical Vapor Deposition (CVD) refers to 350-650 degrees C interval. This temperature range is critical for this process since the thermal and lattice mismatch (or strain relaxation) issues diminish in advanced BiCMOS processing. The modeling of the epitaxy process is a vital task to increase the understanding the growth process and to design any desired device structure. In this study, an empirical model for Si2H6/Ge2H6-based LTE of SiGe is developed and compared with experimental work. The model can predict the number of free sites on Si surface, growth rate of Si and SiGe, and the Ge content at low temperatures. A good agreement between the model and the experimental data is obtained.

Bi-CMOS, Device structures, Disilanes, Empirical model, Experimental data, Ge content, Growth process, Kinetic modeling, Low temperature epitaxies, Low temperatures, Si surfaces, Temperature range
National Category
Electrical Engineering, Electronic Engineering, Information Engineering
urn:nbn:se:kth:diva-95132 (URN)10.1149/2.jes113689 (DOI)000302211800059 ()2-s2.0-84859327130 (Scopus ID)

QC 20120515

Available from: 2012-05-15 Created: 2012-05-14 Last updated: 2017-12-07Bibliographically approved

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