Planar bipolar transistors including heterojunction transistors

摘要

A bipolar transistor is constructed to include a substrate, a collector layer epitaxial grown on the substrate and a base layer ion implanted in the collector layer. Next a further epitaxial layer is grown on the collector layer over the ion implanted base layer. A base contact region is ion implanted in this further epitaxial layer between the surface of this further layer and the base layer. The base contact region surrounds and defines an emitter in the further layer. A base ohmic contact is formed on the surface of the further layer in a location overlaying and contacting the base contact region. An emitter ohmic contact is also formed on the surface of the further layer in contact with the emitter. Additionally a collector ohmic contact is also formed on this same surface in a position isolated from the emitter by the base contact region. The collector ohmic makes an electrical contact with the collector by utilizing the further layer as a contact pathway.