Book reviewed by Peter M. Dryburgh
A Jewel in the Crown
A history of crystal growth research at RRE/RSRE, Malvern, UK
Donald T.J. Hurle & Keith G. Barraclough
PUBL: Aspect Design 2014, Malvern, Worcs. WR14 1PD
2014 126pp £9.99
In 1945, the wartime work of the Telecommunications Research Establishment (TRE) and the Radar Research and Development (RRDE), both situated in Malvern, Worcestershire, came formally to an end. Although the war was over, it was realised that there could be no question of stopping research and development in the crucially important fields of electronics and optics so, in 1953, the two establishments were united to form the Royal Radar Establishment (RRE). In 1976, RRE became The Royal Signals and Radar Establishment (RSRE). As a result of a later government’s enthusiasm for privatisation, RSRE was eventually floated on the London Stock Exchange as QinetiQ plc. This book traces the development of the establishment but is primarily concerned with the hugely influential work on crystal growth which was carried on for over thirty years.
It is still not widely appreciated – even by many scientists and engineers – that the growth of single crystals is the foundation upon which most modern technology is built. Without the work of crystal growers, there would be no electronics industry, no computers, very little optical industry and some important gaps in conventional production engineering. Many types of single crystal are required for lasers, optical components for spectroscopy and detection, scintillators for nuclear physics, diode light-sources, bearings, gemstones and innumerable other applications. Between 1960 and 1990, RRE/RSRE was one of the most important crystal growth laboratories in the world and its workers were responsible for an astonishing list of important discoveries and inventions.
The evolution of the establishment is covered in some detail in Chapters 1&2, a few pages being devoted to a useful introduction to the terminology of crystals and crystal growth. This is followed by brief review of how the need for infra-red detectors and germanium and silicon dominated the early work and how the theory of constitutional supercooling was applied by Hurle to crystal growth, especially in the use of the crystal puller designed by Bardsley and Green.
The development of high-pressure pulling, introduced by Mullin and co-workers
extended the application of the pulling method (known commonly as the Czochralski technique) to the growth of the III-V compounds, such as gallium phosphide and arsenide, whose melts have high dissociation pressures.
The recognition that crystal growth was a discipline in its own right was accepted somewhat reluctantly in some scientific circles and, in Chapter 4 the authors describe how but the first international conference on crystal growth (ICCG1) was followed by 5 years of international development and the formation of a number of national crystal growth organisations. The Journal of Crystal Growth was first published in 1967 by the North Holland Publishing Company (later Elsevier), the International Organisation of Crystal Growth (IOCG) having been formed in 1966 with its first president Sir Charles Frank.
Later chapters deal with the automation and control of crystal growth equipment, with the transfer of technology to industry and the various changes of emphasis brought about by changes in government policy.
By the nineteen-eighties, the problems associated with the growth of the ever larger silicon crystals required by the electronics industry had focussed attention on the hydrodynamics of melts and the Malvern workers were pioneers in applying magnetic fields to damp the effects of convective instabilities. These developments are discussed in detail in Chapter 9.
Chapter 10 deals with the important fields of epitaxial thin films, particularly concerning the application of organometallic compounds. A great triumph of the Malvern workers was the successful growth of thin layers of cadmium mercury telluride (CMT) for near infra-red detectors, a process of formidable technical difficulty. CMT is probably the most intractable crystalline material ever required for device production. The technique of molecular beam epitaxy (MBE) also became important at this time and was actively pursued.
Later chapters explore the important part played by the Malvern workers in fostering international interest in crystal growth and organising international conferences.
This book is concentrated and full of detail, both technical and historical, but is easily read, particularly if the reader was involved in crystal growth work during what is often regarded as the “golden era” of 1970-1990. The authors have managed to produce a short book which comprehensively describes both the work of a very special institution and the historical development of an important field of science and technology. Both text and pictures have been meticulously edited.
The constant changes brought about by government fashions cannot obscure the fact that a state run organisation can be monumentally successful and the driving force behind the creation of successful specialist companies: the history of electronic materials work at Malvern shows this very clearly. Anyone interested in the fields of crystal growth or, indeed, the history of modern technology, should read this book, and any politicians who believe they can organise scientific research should consider its story very seriously.
About the BACG Since 1969 the BACG has encouraged national and international scientific and technological communication and discussion of the theory and practice of crystal growth, crystallisation and the appraisal of crystals. The Association has...