Silicon gate complementary MOS structure with field shield

Conventional aluminum gate complementary MOS transistor structures normally have the p-channel transistor fabricated in a low concentration ( impurity atoms/cm³) (1,0,0) oriented silicon substrate and the n-channel transistor fabricated in an isolated p-type "well" with a surface concentration on the order of 10¹⁶impurity atoms/cm³diffused into the n-type substrate. If silicon gate technology is to be implemented for CMOS structures of similar background concentrations with a p-doped gate used for the p-channel transistors and an n-doped gate used for the n-channel transistors, the p-channel devices tend to be in depletion mode which is undesirable for switching circuits.