Preface to the First Edition

P r e f a c e to t h e first e d i t i o n This book gives an account of the recent work on strained layers and Ge~Sil_~ heterostructure devices. Extensive work has been done on strain, dislocations, and mechanical stability of strained layers, and a large number of papers have appeared on these subjects during the last 15 years. This work is treated in detail in Chapters 2 and 3 and should be useful to engineers and material scientists concerned with effects of strain on the mechanical properties of crystalline layers of any material. The effects of strain on band structure, transport, and optical properties treated in Chapters 3 and 4 are more specific to GeSi strained layers. These chapters form the basis for understanding the design and modelling of strained-layer devices as discussed in Chapters 6 through 8. At the time of this writing, GeSi strained layer heterostructure bipolar transistors and optical detectors have shown great promise. One chapter is devoted to each of these two devices. Field effect devices are discussed in Chapter 8. Other devices that have been fabricated using GeSi strained layers are also discussed briefly in Chapter 8. In addition, this chapter contains a discussion of miscellaneous applications of GeSi alloys. The subject matter is treated at a level appropriate for students and researchers in material science, design, and modelling of semiconductor devices. In a monograph of this size, it is not possible to discuss the entire subject in a comprehensive manner. Excellent books and reviews on the MBE and CVD growth techniques have appeared. Growth technology and processes of device fabrication are not included in the book. However, the merits of the different technologies are discussed. Some four thousand papers of high quality have appeared on strained layers and devices in the last fifteen years. I have quoted over four hundred papers in the bibliography that are most relevant for a coherent discussion of the subject. To make the bibliography more useful, titles of the papers have been included. I must express my gratitude to the late Professor Sir K. S. Krishnan, F.R.S., who taught me the techniques of investigation. I have benefitted from interaction and collaboration with such a large number of colleagues that it is impossible to mention them all individually. Interaction and discussions with my graduate students at NPL, IIT and Solid State Physics Laboratory (all at Delhi) have been very stimulating. My several visits to Harwell Laboratory in the U.K. and interaction with Dr. A. B. Lidiard, Dr. A. E. Hughes, Dr. R. Bullough, Dr. A. M. Stoneham and Dr. A. Atkinson have been particularly useful. A considxi

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erable part of this book was written during the time I worked at the Clarendon Laboratory. I am very grateful to Professor R. A. Cowley and Dr. 3. M. Baker for providing me with facilities at the laboratory. I have derived considerable benefit from my stay at IMEC and as a visiting professor of KU Leuven, TU Aachen and TU Delft. I am indebted to Professor R. Van Overstraeten, Professor R. Mertens and Professor P. Balk for providing me with these opportunities. I wish to extend special thanks to Mr. Charles G. Arthur, Vice President and Associate EditoriM Director of Academic Press for his personal support for this project. He and his colleagues always showed the utmost consideration to me. It was due to the skill and efforts of his colleague Mr. Joe O'Toole that the project could be completed in a relatively short time. He deserves my sincere thanks. The help of Ms. Pascha Gerlinger, head of the production department, was invaluable in removing the deficiencies in the typing and structure of the manuscript. I am grateful to Mr. T. J. Gosling for reading and making valuable comments on parts of the manuscript. Finally, I must thank sincerely my wife Sudha for her unfailing support and help during the preparation of this book. S. C. Jain Clarendon Laboratory April 4, 1994