Manufacturing process for high-frequency bipolar transistors

Claim 1

A process for manufacturing high-frequency transistors which comprises a succession of steps including: diffusing a buried layer into an appropriate substrate; growing an epitaxial layer on said buried layer and said substrate; growing a thin layer of thermal oxide on said epitaxial layer; depositing an oxidation resistant material on said thin oxide; determining and oxidizing insulating regions; determining a base region in the epitaxial layer and implanting therein a doping agent passing through said oxidation resistant material and thin oxide layers; removing the oxidation resistant material except portions in separating zones between contact areas on the substrate; implanting collector and emitter regions in the epitaxial layer under contact areas; annealing and penetrating said implanted base, collector and emitter regions; removing the thin oxide from the contact areas; and metallization of the contact areas.