RCA Transistor Oral History Pankove Page 2

EARLY TRANSISTOR HISTORY AT RCA

Jacques Pankove

Oral History – Jacques Pankove (Continued)

The earliest transistors were of the point contact type. I soon found that the easiest way to make such a transistor was to buy two Western Electric diodes, crack their bakelite case and remove two small pig-tailed cubes of Ge and two tungsten whiskers. With these components it was easy to assemble point contact transistors just like the ones used at Bell Labs. Some of these devices worked, but all were noisy. My first long term study was to measure the transistor performance as a function of whisker pressure.

My immediate supervisor was Dr. Jerome Kurshan, who teamed me with an older, more experienced researcher named Dr. Charles Mueller. Charlie was an expert on small vacuum tubes who had carefully compiled data on every tube type to identify the importance of a small change in the fabrication process. He was very conservative and cautious of innovations. His favorite response to a new suggestion was “Maybe Yes and then, Maybe No.” We worked together to develop the first alloy junction transistors at RCA.

The early years at RCA were exciting. I could try anything I wanted and enjoyed interpreting the results and getting wise inputs from many experienced experts. This was better than graduate school. I also had opportunities to attend conferences and meet other researchers with similar interests, thus getting deeper into the physics and technology of the devices we were making and testing.

Oral History – Jacques Pankove (Continued)

Surface treatment was an important parameter for transistor performance. The summers in New Jersey were quite humid, leading to the discovery of the “hand wave effect” : the collector contact tended to be leaky and noisy, but if you waved your hand near the transistor, the collector characteristic would calm down and stabilize. Hence it became evident that the ambient needed to be controlled. A room air conditioner was installed in the lab. The handwave effect stopped and it felt very good to work in an air conditioned lab. Everyone wanted to switch to semiconductor research! Two years later, the whole building was air conditioned.

Bob Hall at General Electric was doing excellent research in semiconductors and had discovered that an indium contact fused to germanium was rectifying and more stable than a point contact. This led me to replace the tungsten whiskers by two indium dots on opposite faces of a thin germanium crystal. The emitter would inject holes into the base. These holes would then diffuse to the collector where they would be collected. During that period there was interest in the role of surface recombination on the transfer efficiency of holes from emitter to collector in pnp transistors. One RCA engineer, Lloyd Barton, had been assigned to convert electronic circuits from vacuum tube applications to transistor applications. He was quite good at these conversions.

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