In early days when vacuum tubes dominated the electronics market, investigator at Bell Labs such as William Shockley was searching the properties of different semiconductor materials as well as germanium and silicon. At the tile of WW II, radar receivers required diodes reacting adequate to act as frequency mixer elements at microwave frequencies. Classic vacuum tube diodes didn’t react quickly enough, so solid state diodes were used in place of it.

Beginning with low power, low frequency applications such as the ubiquitous "cheap Japanese transistor radio," transistors gradually started to take place of vacuum tubes. As transistors advanced and as circuit designers became known with how to use these new devices, vacuum tubes were relegated to a very few specialized applications. Solid state screens are only today in the process of taking place of the venerable color TV tube.

There were mainly 2 major kinds of transistors that commercial produced. Bipolar junction transistor was the first whose 3 leads were known as base, collector, and emitter. The comparatively tiny current from the base lead was used to control the run of current between the collector and the emitter. The bipolar junction transistor is either PNP or NPN based on how the 3 regions of the transistor were "doped" with impurities to make additional free electrons (N region) or "holes" (P region) where electrons were not there in the silicon crystal structure.

The second kind was the field effect transistor where voltage applied to the gate pin of the device is divided from the semiconductor channel between source and drain by a slight insulator layer or a diode junction in the junction FET. This gate voltage makes an electric field in the channel used to control current flow from the channel between the sources and drain pins of the transistor.

The first successful try to make an integrated circuit were made alone by Jack Kilby working at Texas Instruments and Robert Noyce while working at Fairchild Semiconductor. Kilby began working on a germanium integrated circuit in July of 1958 and filed for a patent on this on February 6, 1959. Noyce's efforts using silicon in place of germanium were about 6 months behind Kilby's, but resulted in a more complicated "unitary circuit" for which a patent was issued April 25, 1961