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K. D. Smith - Memories
By James M. Early Copyright J. M. Early 1990 |
"What people want most out of life, they generally get" said
K.D. Smith one afternoon in the early 50’s. It was, I think true of himself. Despite his deep involvement in work, in family, and in technical hobbies, it was obvious that he and his wife, Laurine, quietly gave much time and attention to community concerns. He earned a good living by hard work, but seemed to seek no additional reward but the pleasures of doing what he could and of knowing he had done his duty as he saw it.
Kenneth D. Smith (usually "K.D.", sometimes "Ken") was my supervisor at Bell Laboratories from my first day there in September 1951 until 1954 or 1955. He began by finding me a desk, either in his own laboratory or the one next door, and indoctrinated me in various aspects of life at "the Laboratories". He assigned me to work with him on transistor characterization and analysis. As a "hands on" supervisor and experimenter, he often sat at a test bench and measured, not to accumulate routine data but to explore points of interest. He taught experiment by doing it.
He directed me and encouraged me, pushing me to use the helps available. Of his technical qualities, the most impressive ones were his curiosity (he was then in his late 40’s, I think) and his adaptability. He was a highly intelligent person and systematic and thorough as well. Most of his Bell Labs career had been in circuit and system work such as development of transmission systems. His transfer into the transistor area without previous device experience reflected, I believe, management’s high opinion of him and his own questing spirit and willingness to adapt. During my first years in semiconductor work, he provided needed guidance, support, and encouragement while letting me go and grow well beyond the assigned tasks.
K.D. was a fine-looking man around six feet tall, strongly built, and already gray-haired. In manner he was scholarly, kind, and a gentleman in every respect. He supervised a small group of engineers engaged in development of grown junction germanium n-p-n transistors. His group was part of R.M. Ryder’s department which had other groups working on point contact transistors.
Both the work Ken gave me, as a new, inexperienced, engineer and Ken’s supervisory style fitted my needs. He set me to characterizing n-p-n grown junction germanium transistors, first the famous M1752, Bell Labs first developmental type, then some GE indium-germanium p-n-p alloy junction transistors, then some similar RCA p-n-p alloy transistors designed to correct a weakness of the GE type.
He listened understandingly and shared my enthusiasm concerning various discoveries. He was the first person, I think, to hear of the "theory of space-charge layer widening in junction transistors", also commonly called "Early Effect".
Ken enjoyed the light side of his job. He told how Mervin J. Kelly, then president of Bell Labs, had taken a British research executive through the transistor laboratory on a weekend and had given him a grown junction germanium transistor taken from K.D.’s desk. The profuse immediate thanks were followed a week or two later by a report of the non-performance of the transistor and, in fact, of the apparent (under x-ray) absence of germanium from it. The Britisher wished to know if the transistor was a typical unit. It was identified as an M1752, coded ZZ followed by a three digit number.
Use of a two-letter code to mark the month of assembly had only begun a year or so earlier and at the other end of the alphabet. Anyone familiar with project details would have spotted ZZ at once as a false date code and asked about it. The date code was not all that was false. The ZZ series weren’t transistors at all but dummies, made to show what transistors looked like.
It was the visitor’s bad luck that M. J. Kelly knew where to find some transistors, but not how to identify a dummy. The fuss made over it did nothing to spoil Ken’s amusement.
Ken not only supervised but also counseled me. He edited proposed papers or memoranda, using clear but kind language and making suggestions that were common sense to follow.
Whatever disagreements we had were resolved so rationally, speedily, and unemotionally that I don’t recall any. He gave me broad instructions for action and encouraged novel ideas, whether of mathematical modeling, physical understanding, or possible device structure. As a result, anything I did usually went to him before any one else.
For example, while sitting next to him at an internal symposium in Bell Labs’ Murray Hill auditorium during April of 1952, I realized that junction transistor base layers should be thin compared to their collector space charge or depletion layers. I turned to K. D. and said that transistors were designed all wrong, with the base thick and the collector barrier thin. My recollection is that neither of us said or thought more about it until late May. Then, one evening at home, out came the concepts embodied in my high frequency transistor patent application, including the "intrinsic barrier transistor". I lay awake most, if not all, that night, contemplating the beauties of the postulated transistor structures and admiring the achievement. The next morning, to my car pool and to Ken, I proclaimed that this was the "ideal junction transistor" or some such. Ken, I believe, not only made no attempt to subdue my enthusiasm but witnessed the notebook entries. What his influence here was is hard to tell. Clearly, his attitude encouraged in many ways, discouraged in none.
A disappointment we shared was our abortive investigation of current multiplication at elevated voltages in the germanium n-p-n grown junction transistors. Calculation indicated that increase of temperature because of power dissipation might just possibly have caused the current multiplication we were seeing. Not satisfied but not seeing other possible explanations or raising the collector voltage further or transferring our experiments to p-n-p alloy transistors, we abandoned the study. Months later we realized that we had seen but not identified "avalanche multiplication" in which charge carriers create new hole-electron pairs by impact ionization, a discovery rightly ascribed to two other Kens, K.G. McKay and K. MacAfee.
K.D. was clear-sighted, tactful, forthright, dependable, technically on top of the job, and a pleasure to work with. On technical matters, our relationship was that of peers working on a problem. Bell Labs was that kind of world, a world where "I don’t know", "I don’t understand", and "My idea was wrong" were easily said, readily accepted, and taken as descriptive. It was a world focused on solving problems that had not been thought of before.
Our last major collaboration was on the Telstar solar cell job. In 1960 or 1961, we were asked to develop n-on-p solar cells for Telstar, I promptly proposed that K. D. be assigned to set up a laboratory fabrication facility capable of making experimental quantities adequate for evaluation of structures and processes.
He was responsible for fabrication and testing and for some aspects of transistor qualification and testing. The latter was not as ground-breaking as the solar cell work, which called for developing and producing an N on P structure, a shallow junction, new contact materials, and some new processes. The design sought high efficiency in conversion of solar energy to electrical energy together with improved resistance to degradation of cell efficiency in orbit. The high energy electron radiation of the van Allen belt and other cosmic radiation were anticipated to be and proved to be major sources of damage.
He also had responsibility for transferring the technology into Western Electric’s Allentown (PA) plant. There were problems galore but the job was done to schedule with most, if not all, the cells which were flown on Telstar I coming from the Western Electric line. Ken’s powers of observation, keen interest, and drive were vital.
Ken wasn’t a workaholic. His hobbies included, among others, amateur radio (building his own, I believe), astronomy (grinding his own lenses), and photography. He was, on the technical side, a bit of a "renaissance man". He and Laurine were family people and he took pride in their sons. One day he commented that, on the previous evening, their older son, then in high school, had waited outside our building to pick K. D. up and take him home. When he got in the car, the boy had told him of watching the men coming out, their faces "filled with thought". We all recognized the truth of the observation and were impressed that a boy should notice.
Working under and with K. D. Smith was one of the formative experiences of my technical career. I am glad of the opportunity to reflect on our work together and pay his reputation the thanks that I never adequately expressed to him. The K. D. Smith semiconductor device collection is a totally appropriate memorial to him. He created the collection. It ought bear his name. - JME
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