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Alternatively you can submit your request online by visiting the Elsevier web site at http://www.elsevier.com/locate/permissions, and selecting, Obtain- ing permission to use Elsevier material Notice No responsibility is assumed by the publisher for any injury and/or damage to persons or property as a matter of products liability, negli- gence or otherwise, or from any use or operation of any methods, pro- ducts, instructions or ideas contained in the material herein British Library Cataloguing in Publication Data A catalogue record for this book is available from the British Library Library of Congress Cataloging-in-Publication Data A catalog record for this book is available from the Library of Congress ISBN: 978-0-444-53240-4 For information on all Academic Press publications visit our website at elsevierdirect.com Printed and Bound in The Netherlands 09 10 11 12 10 9 8 7 6 5 4 3 2 1 PREFACE In 2004 Oxford University Press were generous enough to publish my book “The Story of Semiconductors” which was written for final year undergraduates, research students and research workers in the many aspects of semiconductor physics and applications. For my part it was a labour of love following my retirement from a working life spent almost entirely in the field of semiconductor research, firstly with the Philips company, later at the University of Nottingham. It was motivated by an interest in the fascinating question as to how things happened in a field of such tremendous importance, not only for the development of a vital branch of solid state physics but also for the general betterment of man- kind. Indeed, there can be little doubt that the invention of the transistor and its many counterparts turned western civilisation on its head during the second half of the twentieth century and it seemed to me that students of physics, electrical engineering and materials science should have an opportunity to understand, not only the technical aspects of the subject but at least something of its history. There are, of course, many technical books on semiconductor physics and semiconductor devices and a small number that provide a historical look at certain specific happenings, such as the inventions of the transistor and the integrated circuit but mine was, I believe, the first to cover the whole gamut of semiconductor develop- ments from their early faltering steps in the nineteenth century right through to the millennium. I firmly believe that scientists and engineers should be able to communicate with their peers in the non-scientific world and an appreciation of the context and history of their specialist subjects must surely constitute a vital part of such interaction. It repre- sents a natural point of contact between the two ‘sides’. The book was quite favourably received and has, I hope, helped a modest number of scientists to give thought to the less technical side of their specialities, even, perhaps, to stimulate discussion between them and their non-scientific friends. However, there can be no question that it was a text addressed specifically and exclusively to scientists. There was far too much mathematics and physics in the presentation to permit the general reader to approach it with any hope of serious enlightenment. I might have addressed one side of the divide with modest success but there was still an important, and probably much larger, readership need- ing help to jump the gap from the opposite direction. Why not attempt to provide that help? Why not, indeed? I now had more leisure, with plenty v vi Preface of time to think about the nature of the problem of communication between the ‘Two Cultures’ and the idea gradually took shape for a second attempt to describe the history of my subject with all the mathe- matics and much of the physics removed. Was it possible, I wondered? The answer was a qualified ‘yes’ – I was, at least, in a good position to make the attempt, having given much thought to the historical and political aspects of the subject already. It might be far from easy to maintain a scientifically accurate presentation but I decided to try and, with the welcome encouragement of Elsevier, I have taken the plunge. The present book therefore celebrates the exciting progress made by semiconductor electronics during the second half of the twentieth century and sets it in the wider context of the semiconductor physics which made it all possible. It attempts to explain the complexities of highly technical developments in such a manner as to be intelligible to the general reader who is prepared to make a serious effort but above all it tells a fascinating story. I sincerely hope that it will help him or her to gain a deeper understanding and, in so doing, find the same kind of pleasure and satisfaction experienced by those scientists who have been more directly involved in the chase. As an example of human achieve- ment it must rank alongside the Beethoven symphonies, Concord, Impressionism, mediaeval cathedrals and Burgundy wines and we should be equally proud of it. I only hope that my attempt to explain something of its appeal will help the layman to obtain the same kind of enjoyment from an understanding of semiconductor electronics that he or she might experience in contemplation of any of these. My own experience in both Industry and University leant ever so slightly towards material science and I have therefore adopted an approach which highlights this aspect. It is part of my thesis that materials are vital to any form of engineering and a proper appreciation of the part they play is essential to any real understanding of such developments. I have tried, in a very brief introduction, to highlight the role of materials in a range of other human activities and have used this to point up their very similar role in the field of semiconductor devices and systems. I hope this will help the reader’s appreciation of the many parallels to be found between the present subject and others with which he or she may be more familiar. It is also a central tenet of my presentation that materials form a link between the various different aspects of the subject, namely those of basic physics, technology and practical engineering. There is a vital inter- play between each of these which enhances all three together and many examples will be found in the following account. Again, I hope that I have made clear just how things happen in the real world of science and technology and how scientists themselves influence this. It should never be forgotten that scientists are only human and that science makes prog- ress in much the same chaotic fashion as do most other human activities. Preface vii The idea that science is somehow ‘different’ should be firmly dismissed and I hope that this book may help, if only slightly, in dismissing it. While I take full responsibility for all errors, inconsistencies, obscu- rities, misrepresentations and clumsiness of expression that may have crept into the text, I should none-the-less like to record my grateful thanks to various people who have helped me in putting this book together. Brian Fernley, Mike Seymour and Maurice Tallantyre read sections of the manuscript and offered helpful comments. My wife, Joyce, not only put up graciously with long hours of effective separation but also helped with the writing of this preface. My thanks are also due to all those people with whom I have enjoyed stimulating working contact over the years, particularly those Philips colleagues in Redhill and in Eindhoven and Limeil. Without their help I could scarcely have acquired an understand- ing of semiconductor physics adequate to the task of explaining it to others. Orchard Cottage October 2008 CHAPTER 1 What Exactly is a Semiconductor: and what can it do? For many people, the run-up to Christmas 1947 probably represented a welcome return to some semblance of peaceful normality following the end of the Second World War hostilities. But at the Bell Telephone Laboratories in Murray Hill, NJ something altogether more significant was in the air. On 16 December Walter Brattain and John Bardeen, senior members of William Shockley’s Solid State Physics Group, observed for the very first time the phenomenon of electronic power gain from their Heath Robinson arrangement of springs and wires, connected to a small piece of germanium crystal. The culmination of two years of concentrated effort, this was the world’s first solid state amplifier and the world was never to be quite the same again. In terms of its long-term impact on human life, the transistor (as it soon came to be known) was probably of far greater significance even than the war which had so recently ended – and which had, incidentally, contributed considerably to its development.