Transistors with reduced surface level - differences

摘要

Thin layer of dielectric, which can be attacked selectively relative to SiO2 and can be a diffusion barrier for O2- ions and acts as a screen against oxidation, is deposited on a silicon slice. It is masked and attacked to disclose Si in zones where a thick oxide layer is required; the layer is produced by thermal oxidation. The dielectric is selectively removed and known steps areused to produce as MOS or bipolar transistor or a diode. Preferably the dielectric is Si3NH4 or Al2O3, or a Si oxynitride.