The metal-oxide-semiconductor field-effect transistor (MOSFET) was invented in 1960. The processing technology required for suc- cessful high volume fabrication became available in 1968. The use of doped polycrystalline silicon as the gate electrode, instead of aluminum or some other metal, resulted in substantial enhancement in performance. Efforts to improve the properties of MOS devices produced new structures such as: CMOS, MNOS, SOS, VMOS, DMOS, FAMOS, etc. In recent years a great deal of work has been done to study the fabrication and properties of MOSFET's. There are two reasons for...