Process for making field effect and bipolar transistors on the same semiconductor chip

Claim 1

Method for manufacturing an integrated circuit structure having dielectrically isolated regions containing bipolar and field effect transistor devices comprising: providing a silicon monocrystalline substrate; etching said silicon in the areas to be the dielectric regions isolating the said field effect transistor devices; oxidizing the exposed silicon in said regions to form first oxidized areas; etching said silicon in the areas to be the dielectric regions isolating the said bipolar devices to form a mesa in the center of the etched area; oxidizing the exposed silicon areas to form a screen oxide area; ion implanting impurities through said screen oxide areas to form the subcollector for a bipolar device; growing thick silicon dioxide in said screen oxide areas to completely fill the areas with silicon dioxide and complete said dielectrically isolated regions; simultaneously forming the source, drain and emitter regions of said devices; forming gate insulator and gate electrodes for said field effect transistor devices; forming electrical contacts to said source, drain, gate, emitter, base and, collector of said devices.