Method for preparing a non-self-aligned heterojunction bipolar transistor with a small emitter-to-base spacing

Abstract

The present invention refers to a method for preparing a non-self-aligned heterojunction bipolar transistor comprising: preparing a patterned emitter metal on an emitter epi layer of a HBT epi structure on a substrate; preparing an emitter epitaxy below the emitter metal; applying a resist layer on the top surface covering the emitter metal and emitter epitaxy, and the base layer; applying lithography leaving the emitter epitaxy and the emitter metal covered by the resist vertically with a width pD and leaving a pattern according to the mask in the resist; depositing base metal on the entire surface; and removing the remaining resist and the base metal covering the resist defining a base metal, the base metal being spaced from the emitter epitaxy and the emitter metal by a distance xD from 0.05 μm to 0.7 μm. The present invention refers to a non-self-aligned heterojunction bipolar transistor as prepared by this method.

Dependencies are inferred from the claim text.