• Patent

Method of manufacturing heterojunction transistors with self-aligned metal contacts

A method of manufacturing heterojunction transistors having

self-aligned contacts. In manufacturing a heterojunction bipolar

transistor, a collector and a base layer are deposited on a

substrate. A masking layer is deposited on the base layer and

selectively etched to form an aperture therein, exposing the base

layer. An emitter having a mesa structure is grown epitaxially on

the exposed base layer to produce lateral overhang portions. The

overhang portions may be formed by continuing the epitaxial growth

to form lateral overgrowth portions overlapping the masking

material. The masking layer is removed and self-aligned contacts

are formed to the base and emitter regions using the lateral

overhang portions which provide separation between the emitter

structure and the contacts to the base layer.

Citation

Enquist, P., & Slater, D. B. (1993). IPC No. U.S.Method of manufacturing heterojunction transistors with self-aligned metal contacts (Patent No. 5272095.)