Oral history of British science

Hilsum, Cyril (Part 14 of 25)

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  • Recording locations

    Interviewee's home, Middlesex

  • Interviewees

    Hilsum, Cyril, 1925- (speaker, male)

  • Interviewers

    Lean, Thomas (speaker, male)

  • Abstract

    Part 14 [1:45:41][Interview Five: 12 April 2012] Comments on starting work at RRE Malvern: excellent welcome; wider implications of Sutton's destruction of SERL semiconductor group, Ian Ross sent to Harlow, CVD confusion; Malvern's earlier work on Silicon by Alan Gibson, Malvern happy to have CH's semiconductor expertise at his rank; transfer of CVD contracts to Malvern; [05:30] departure of Robin Smith from Malvern to Sheffield; CH settling in to Malvern, initially sharing office with engineer Mercer; CH wanting to take work in two directions, semi-conductor laser and transferred electron device; 1965 development of first microwave oscillator in semiconductors. [09:10] Comments on radar: description of use of microwave oscillator in radar set to produce radar beam, improving on Harry's Boot's wartime magnetron by allowing smaller, X-band, wavelengths and smaller radar sets; [15:25] level of improvement of semi-conductor radar over previous systems, testing of system in long range communications; importance of local oscillator to mix signals of radar and circuitry frequencies; Doppler effect and Doppler radar, as used in police speed-cameras and security systems. [21:40] Comments on Malvern open days: anecdote about displaying Doppler radar security system to school children at a Malvern open day; regular open days; variable security of work at Malvern; [25:25] anecdote about publicity around radar speed gun disrupting a social evening for CH, resulting in CH on the front page of the 'News of the World'; Malvern philosophy compared to Baldock, greater support of mathematicians and theoretical physicists; [28:45] Description of mechanisms inside semi-conductors: theory of hot electron effects; Malvern theoreticians Paul Butcher and Bill Fawcett working with CH and David Rees on calculations; assistance of computer for running Monte Carlo calculations; eventual ability to work on theoretical, perfect, semiconductors. [32:15] Remarks on computers: writing their own programs on punched tape; assistance of maths group; changes in computing and programming languages, ALGOL; assistance writing programs; computer group running computer all night on their programs. [34:35] Description of mechanisms inside semiconductors and their use: frequency dependent on interaction of crystal and environment; design of cavity for crystal; need to understand mechanisms inside crystal; domains within semiconductor and determination of frequency by transit time through semiconductor; higher frequency radar sets, desire to function in Q band; need to stop domains forming to increase frequency; theorisation of domains as a spaced charge of electrons; cathode experiments. [40:35] Comments on role of industry consortium in development: work between Baldock and Plessey at Caswell; Plessey success at producing pure layers of gallium arsenide from the gas phase; problems with impurities; ability to make better transferred electron devices with pure gallium arsenide; share of information through consortium, Mullard production of oscillator, based on work of SERL, STL, Plessey and Marconi; anecdote about CH conversations with Mullard over pricing of oscillator, and Plessey and STL following Mullard's example. [47:00] Comments on: CH status as leader in III-V compound work; CH paper at 1964 talk on III-V compounds at international conference on physics of semi-conductors; international status of work; CH work on complications in band structure of semi-conductors; alloying of gallium arsenide and gallium phosphide to create larger energy gap, resulting in visible light LEDs; CH paper at 1968 Moscow conference on indium gallium phosphide; band-structure engineering, mixing different semi-conductors to optimise effects; CH work on indium phosphide instabilities with David Rees. [54:40] Comments on CH work with David Rees on indium phosphide: discovery of a third level of electron transfer in semi-conductor; X, K and L levels; anecdote about publishing of work and subsequent citation record success, opinion of many that theory was wrong, even though it worked well in practice. [1:00:50] Comments on: analysing literate on materials and developing a pattern of how things different semiconductors work; description of charge transfer in semiconductor lattice, change of strength of charge in different III-V compounds; representation of electrons moving in cup as having an effective mass; scattering mechanisms, band structures; movement of electrons in cup, effects of different energy levels. [1:06:30] working to develop a pattern of how materials function; mobility of electrons relation top scattering mechanisms, temperature and purity of material; developing a feel for effects, rather than accurate understanding; neglected study of indium phosphide; research attitudes at time leading to neglect of some topics in favour of others; importance of having a feeling for topic. [1:11:00] Comments on work activities at Malvern: spending much day talking to people; women valve-assemblers building semi-conductor devices; group made up of people making and measuring devices, theoretical physicists and interaction with materials division; growing of single crystals at pressure; CH and Brian Mullin idea of liquid encapsulation for pulling crystals through materials; [1:19:00] importance of having single crystal semiconductor, lower cost solar cells benefiting from improvements in making large silicon crystals; CH starting work on indium phosphide, in spite of difficulties, because it worked better; anecdote about recruiting a female scientist, Jenny Welborn, who left to work on radiotherapy due to disliking competitive atmosphere at Malvern; CH impression of friendly competition at Malvern, not always knowing what people were doing; anecdote about people joining CH's group unofficially; CH handling contracts. [1:25:00] Comments on: conferences, importance of free discussions to development of semiconductors; Device Research Conference in USA; importance of defence research funding and industrial laboratories, rather than universities, with example of early semi-conductor laser work; [1:28:25] advantages of having government labs and industry working on semi-conductor research rather than universities. [1:29:30] Comments on importance of conferences: feeling that Europe needed a semiconductor conference; problematic yearly solid state physics conference in UK at Manchester in winter, anecdote about CH organising secretary and attempting to move conference date and place; German semiconductor device conference, CH interaction with Walter Heywang anecdote about Philips’ Leo Tummers asking them to form one conference rather than two, expansion of conference to cover solid-state more widely, decision to use English as working language; European Solid-State Device Research Conference [ESSDERC], first held in early 1970s at Munich, Lancaster and Nottingham; [1:35:30] anecdote about Frenchman Maurice Bernard complaining that France should be included [pause 1:36:20]. Story about disagreement over the conference official working language: Heinz Beneking objecting to use of French language; CH resolution of situation by removing official language requirement, but also translation facility, leading to de-facto use of English; [1:42:20] long term success of conference, integration of semiconductor circuit conference; CH, Tummers and Heywang honoured at recent 25th anniversary conference; critical importance of conference, venue for community to come together, open sharing of ideas.

  • Description

    Interview with physicist, Cyril Hilsum

  • Related transcripts

    Cyril Hilsum interviewed by Thomas Lean: full transcript of the interview

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    Visit this interviewee's page on the 'Voices of Science' web resource

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