EARLY TRANSISTOR AND DIODE HISTORY AT BELL LABS Art Uhlir Jr.
Oral History – Art Uhlir Jr. (Continued)	Oral History – Art Uhlir Jr. (Continued)
“Porous silicon” (PSi) became more interesting after scanning electron microscopes were available to examine its structure. In the decades that followed our publication, there may have been hundreds of papers written about the varied structures obtainable according to orientation, doping, electrolyte, and current densities. Surely one of the fascinations of this research was that the highly-perfected single-crystal silicon gave reproducible results, however intentionally varied. Many of these researchers must have been chagrinned that, after years of work, it was not they but Leigh Canham who discovered visible light emitted upon irradiation with ultraviolet. We instead are gratified to see ramifications of our modest report being pursued far afield in both industry and academia. There was never a thought by Bell of patenting the material itself. Nor did we disagree with that position. Bell then did not want the political liability of seeming to be a “patent mill” profiting from research paid for by its customers or the government. Those who discern compelling applications may be considered real inventors. One wonders if earlier discovery of light emission from porous silicon might have distracted researchers from compound semiconductors, which do work very well.	In particular, Army Private Nick Holonyak had been sent on attached duty to see if our micromachining technique could drill holes in semiconductors to form grids for transistors more analogous to vacuum tubes than the bipolar junction transistor. We thought there would be easier ways to make much faster unipolar transistors. He attached himself to those exploiting diffusion in silicon for the rest of his tour. But he concentrated on compound semiconductors in his subsequent industrial and academic careers, for which Professor Holonyak recently received the IEEE Medal of Honor AND the Presidential Medal for Technology. The strongest impression we got from the conference was the excitement imparted to young researchers of doing new things, and the example set to them by their elders of diligently entertaining and testing alternative interpretations of observations. ______________
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