# Why did Shockley's Copper Oxide Field Effect Transistor fail and has anybody succeed in creating a Copper as appose to Silicon based FET?

Reading Tomas Lee's very interesting historic account of Semiconductor's used in the Electronic industry:

https://web.stanford.edu/class/archive/ee/ee214/ee214.1032/Handouts/HO2.pdf

I wondered, why did Shockley's Copper Oxide Field Effect Transistor fail and has anybody succeed in creating a Copper as appose to Silicon based FET since?

What was the advantage of Copper over Silicon?

• Would Electrical Engineering be a better home for this question? – Qmechanic Dec 29 '17 at 16:31
• A device physicist is better to answer this because this part of Engineering tends to be handled by physicists. – onepound Dec 29 '17 at 16:34

The problem with the realization of a working metal-insulator-semiconductor (MIS) field-effect transistor (FET) is the interface between the semiconductor and the insulating dielectric. This was obviously also the case with the experiments on the semiconductor cuprous oxide ($Cu_2O$), which was historically used as a rectifier. John Bardeen (double Nobel prize winner in Physics) found that this problem is caused by interface states at the insulator/semiconductor interface which hinder the penetration of the electric field into the semiconductor thus preventing the modulation of a mobile charge layer (conducting channel) near the surface necessary for the field effect transistor. In the course of the experimental investigation of this problem with conducting probes on the semiconductor surface (germanium), Bardeen together with Brattain serenpitously discovered the bipolar transistor effect which led to the realization of the point contact bipolar transistor and later the junction bipolar transistor. Very few insulator/semiconductor interfaces have low enough interface state densities to be suited for a field effect transistor. Only in 1960 the first operating MISFET was demonstrated by John Atalla and Dawson Kahng. This FET, a metal-oxide-semicondoctor field effect transistor (MOSFET), used a specially prepared $SiO_2$ film on silicon ($Si$) to obtain an interface with very low interface state density. Today, MOSFETs are still the most produced electronic devices in the world. Billions can be found on a single commercial processor chip.