Radiation Effects in Advanced Semiconductor Materials and Devices

424 Pages·2002·17.73 MB·English

by  Prof. Cor Claeys, Dr. Eddy Simoen (auth.)

Springer Series in
MATERIALS SCIENCE 57
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C. Claeys E. Simoen
Radiation Effects in
Advanced Semiconductor
Materials and Devices
With 331 Figures
Springer
Prof. Cor Claeys
Dr. Eddy Simoen
IMEC Leuven/Belgium, Kapeldreef 75, 3001 Leuven, Belgium
Series Editors:
Prof. R. M. Osgood, Jr. Prof. Dr. Jiirgen Parisi
Microelectronics Science Laboratory Universitat Oldenburg
Department of Electrical Engineering Fachbereich Physik
Columbia University Abt. Energie-und Halbleiterforschung
Seeley W. Mudd Building Carl-von-Ossietzky-Str. 9-11
New York, NY 10027, USA 26129 Oldenburg, Germany
Prof. Robert Hull
University of Virginia
Dept. of Materials Science and Engineering
Thornton Hall
Charlottesville, VA 22903-2442, USA
ISSN 0933-33X
ISBN 978-3-642-07778-4
Library of Congress Cataloging-in-Publication Data
Claeys,C:
Radiation effects in Advanced Semiconductor Materials and Devices I C. Claeys; E. Simoen. - Berlin;
Heidelberg; New York; Barcelona; Hongkong; London; Milan; Paris; Tokyo: Springer, 2002
(Springer series in materials science; v. 57) (Physics and astronomy online library) - Includes
biographical references.
ISBN 978-3-642-07778-4 ISBN 978-3-662-04974-7 (eBook)
DOI 10.1007/978-3-662-04974-7
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Preface
There is a growing tendency for using commercial state-of-the-art microelectronic
components for space applications. This is driven, on the one hand, by the so
called custom-off-the-shelf (COTS) approach, where commercial components and
circuits are increasingly replacing dedicated expensive radiation hardened elec
tronics. On the other hand, scaling of silicon technologies brings about an inherent
hardening against permanent damage, as thin gate dielectrics become less and less
prone to it. Furthermore, the use of smart or integrated sensors and MEMS will
further stimulate the use of silicon microelectronics in space and other radiation
environments, like CERN's future Large Hadron Collider. In fact, in the ultimate
limit of scaling, complete systems-on-chip (SOC's) are expected to emerge, com
bining different technologies and new materials on the same substrate. Further
more, in order to meet the requirements of the International Technology Roadmap
for Semiconductors (ITRS), scaling of the main technology (CMOS) will require
the use of novel materials and processing steps. For example, SiGe epitaxy will be
implemented more and more for high-speed telecom applications, replacing III-V
materials. Novel gate dielectrics (high-k materials) and intermetallayer dielectrics
(low-k) will be introduced. Ferroelectrics are becoming of growing interest for
memory applications. Device isolation in upcoming technologies will no longer be
achieved by LOCOS techniques but requires advanced schemes like Shallow
Trench Isolation. For high-speed satellite communication and for on-chip commu
nication, the use of opto-electronics will strongly increase. At the moment, most
of the components and systems are based on direct-gap 111-V materials, but there
is intensive search for silicon-based and silicon-compatible optical interconnects.
Powering of satellites is based on solar energy conversion using low-weight high
efficiency tandem solar cells. Currently, the system GaAs on Ge substrates is fmd
ing progressive application in satellites. The future use of so-called nano-satellites
will trigger the implementation of state-of-the-art microelectronic components and
>ystems.
It is clear from the above that these developments in the semiconductor indus
zy are not driven primarily with space applications or radiation hardness in mind.
[t is felt, therefore, that there is a need to have a clear view of potential radiation
iamage problems, even at an early stage of the development of the latest technol
)gy generations. This is not only important for the space community itself but can
)e beneficial during the process/technology development as well. The reason is
:hat during device or circuit fabrication more and more processing steps use an
iggressive environment where irreversible radiation damage can occur. So a fun
iamental understanding of radiation damage mechanisms and degradation is not
VI Preface
only of use for the nuclear/space engineer, but may be helpful for the process en
gineer as well. This monograph is oriented in the first place towards post-graduate
researchers who want to enter the field and wish to obtain a good overview of the
radiation damage in semiconductor materials and advanced devices. A background
in semiconductor and device physics and its interaction with radiation is assumed,
although some basic concepts will be briefly summarized. Furthermore, whenever
possible, an outlook towards future developments and experimental or modeling
needs/shortcomings is provided so that even for the experts in the field, the book
could provide significant added value.
The book contains 9 chapters and analyses radiation effects in a variety of
semiconductor materials and devices. A kind of justification for the book and a
brief discussion of the different radiation environments are addressed in Chap. 1.
Information is also given about the component selection strategies for space appli
cations. The basic radiation damage mechanisms in semiconductor materials and
devices form the subject of a second chapter. A good fundamental insight into ma
terial science and device physics is essential for a proper understanding of the fol
lowing chapters. Chapter 3 reviews the knowledge related to displacement damage
in group IV semiconductor materials such as silicon, germanium and silicon
germanium alloys. Attention is mainly paid to the present understanding of the
fundamental mechanisms involved. The potential and drawbacks of several char
acterisation techniques are outlined whenever appropriate. The device applications
of these materials are discussed in later chapters. Due to its importance for both
micro- and opto-electronics applications, a fourth chapter is devoted to GaAs. Ra
diation aspects of silicon bipolar technologies, including vertical bipolar junction
transistors (BJTs), lateral transistors and SiGe heterojunction bipolar transistors
(HBTs) are critically reviewed in Chap. 5. As already mentioned in the introduc
tion, the key microelectronic technology, which is also driving the activities for
scaling down the minimum feature size, is based on CMOS. The corresponding
radiation aspects are studied in Chap. 6. Important issues such as ultra-thin gate
oxides, alternative gate dielectrics based on nitrided and reoxidised nitrided oxides
and device isolation are covered. A special section deals with silicon-on-insulator
(SOl) CMOS technologies, as they are no longer limited to niche markets but are
also gaining more and more interest for commercial applications. GaAs-based
field effect transistors, such as MESFETS and HEMTs and their radiation re
sponse are reported in Chap. 7, while the opto-electronic components for space are
given attention in Chap. 8. Attention is also paid to different types of components,
including light emitting diodes (LEDs), laser diodes, photodetectors and optocou
plers. Due to space restrictions not all potential advanced semiconductor materials
and devices can be covered in the book. Therefore the last chapter only briefly ad
dresses some hot topics such as non-volatile memories, high-k dielectrics for 100
nm and beyond CMOS and SiC and gives an outlook on component requirements
for future space applications.
As the advances in the field are appearing so fast, a book can only give the
status at a certain moment in time. Therefore the aim was not to look for com
pleteness, but rather to lay a sound physical basis and to give a critical overview of
the type of semiconductor materials and devices presently used for microelectron-
Preface VII
ics in a radiation environment and to focus attention on some emerging technolo
gies with a strong potential for use in future space missions.
Over the years a large number of scientists and researchers from all over the
world have greatly contributed by their discussions and critical comments to en
large the knowledge of the authors in the radiation field. The authors are in the
first place very grateful to all their past and present IMEC colleagues in the field
for stimulating discussions over the years. A special word of thanks has to go to
ESTEC who has financially supported the radiation research activities during the
past 15 years. A large part of the book is based on numerous discussions with L.
Adams, B. Johlander, R. Harboe-S0rensen and A. Mohammadzadeh. The authors
also wish to acknowledge Ms. Kathleen Mertens for her support with the scanning
of the figures.
Leuven, April 2002 Cor Claeys
Eddy Simoen
Table of Content
Preface
List of Acronyms
List of Symbols
List of Greek Symbols
1 Radiation Environments and Component Selection Strategy_ ________________ _!
1.1 Introduction_ _________________________________________________________________________________ 1
1.2 Radiation Environments ______________________________ -------------------------__________ 1
1.2.1 Space Environments _____________________________________________________________ 2
1.2.2 High-Energy Physics Experiments _________________________________________ _3
1.2.3 Nuclear Environment_ ___________________________________________________________4
1.2.4 Natural Environment ____________________________________________________________ 5
1.2.5 Processing-Induced Radiation ________________________________________________ 6
1.3 Component Selection Strategy ________________________________________________________ 6
1.4 Conclusion 8
2 Basic Radiation Damage Mechanisms in Semiconductor
Materials and Devices_ _______________________________________________________________________ 9
2.1 Introduction_ _________________________________________________________________________________ 9
2.2 Fundamental Damage Mechanisms __________________________________________________ 9
2.2.1 Nomenclature ______________________________________________________________________ 9
2.2.2 Ionisation Damage _____________________________________________________________ 10
2.2.3 Displacement Damage ________________________________________________________ 12
2.3 Impact of Radiation Damage on Device Performance _______________________ 20
2.3.1 Ionisation Damage _____________________________________________________________ 20
2.3.2 Displacement Damage ________________________________________________________ 28
2.4 Spectroscopic Study of Microscopic Radiation Damage_ ___________________ 37
2.4.1 Electron Paramagnetic Resonance (EPR)___ ____________________________ 37
2.4.2 Deep Level Transient Spectroscopy (DLTS) __________________________ 43
2.4.3 Photoluminescence Spectroscopy (PL) __________________________________ 49
2.5 Conclusion 51
X Table of Content
3 Displacement Damage in Group IV
Semiconductor Materials_ __________________________________________________________________ 53
3.1 lntroduction ________________________________________________________________________________ 53
3.2 Displacement Damage in Silicon_ ___________________________________________________ 54
3.2.1 Radiation Defects in Silicon_ ________________________________________________ 54
3.2.2 Impact of Radiation Defects on Silicon Devices_ _____________________ 62
3.2.3 Substrate and Device Hardening ___________________________________________ 66
3.2.4 Summary Silicon Radiation Defects ______________________________________ 69
3.3 Displacement Damage in Germanium_ ____________________________________________ 70
3.3.1 Potential Applications of Ge _______________________________________________ _70
3.3.2 Cryogenic Irradiation of Ge _________________________________________________ 71
3.3.3 Room Temperature Irradiation of Ge_ ___________________________________ _74
3.3.4 Impact Radiation Damage on Ge Materials and
Device Properties _______________________________________________________________ 76
3.3.5 Summary Germanium Radiation Defects ______________________________ _77
3.4 Displacement Damage in SiGe Alloys ____________________________________________ 78
3.4.1 SiGe Material Properties and Applications ____________________________ _78
3.4.2 Radiation Damage in SiGe·------------------~-------------------------------83
3.4.3 Processing-Induced Radiation Damage in SiGe ______________________ 95
3.4.4 Radiation Damage in SiGe Devices_ ___________________________________ _103
3.4.5 Conclusions Radiation Damage in SiGe Alloys ____________________ 107
3.5 General Conclusions Group-IV Serniconductors ____________________________ 107
4 Radiation Damage in GaAs _____________________________________________________________ _109
4.1 lntroduction ______________________________________________________________________________ 109
4.2 Basic Notations and Definitions ___________________________________________________ 110
4.3 Native and Radiation-Induced Point Defects in GaAs _____________________ 111
4.3.1 Native Point Defects in GaAs _____________________________________________ 112
4.3.2 Basic Radiation Defects in GaAs ________________________________________ 114
4.3.3 Neutron and Ion Radiation-Induced Defects
in GaAs __________________________________________________________________________ 119
4.3.4 Processing-Induced Radiation Defects in GaAs ___________________ _122
4.3.5 Summary Radiation Defects in GaAs _________________________________ _126
4.4 Damage Factors and NIEL __________________________________________________________ 127
4.4.1 Carrier Removal and Mobility Degradation
inGaAs 127
4.4.2 Correlation between Resistance Damage
Factor and NIEL ______________________________________________________________ 132
4.4.3 Lifetime Damage Factor and NIEL _____________________________________ 133
4.4.4 Correlation with Microscopic Damage ________________________________ 135
4.4.5 Summary Damage Factors and NIEL in GaAs _____________________ _138
4.5 Impact on GaAs Devices ____________________________________________________________ 139
4.5.1 Schottky Barriers and Radiation Detectors __________________________ _139
4.5.2 GaAs Solar Cells _____________________________________________________________ _140
4.6 General Conclusions 143