TABLE OF CONTENTS Once the first stable MOSFETs had been created in the early 1960s by RCA researchers Steve Hofstein and Fred Heiman, and by Dr. Frank Wanlass at Fairchild Semiconductor, it opened the door to researching and developing other types of MOS transistors. This included small-signal complementary-MOS (CMOS) devices, which would theoretically have both N-channel and P-channel transistors coexisting on the same chip together. Although other researchers around the world had tried, no one had yet succeeded in doing this. It was an uncharted area, considered by many to be a lost cause. However, everyone agreed that in theory it was a wonderful concept, particularly for switching functions such as in digital logic gates. The N- and P-channel devices would consume minute amounts of power only during switching (when compared with TTL logic gates), but how to get both types on the same chip was what eluded everyone.
In 1963, Dr. Frank Wanlass at Fairchild Semiconductor discovered that the cause of instability in making MOS devices was trace amounts of sodium. Once the sodium was eliminated, his MOS transistors were perfectly stable. Soon after this discovery, he focused his attention on CMOS, for which he saw a great future. Unfortunately, he could not get his process to work properly because of processing problems. This was a huge technical challenge at the time, but despite not being able to get the device to work properly, he wrote a patent for it anyway. In 1963, Fairchild Semiconductor was granted...
