Patent ID: 7229874

Claim:
A method of forming a structure allowing formation of a self-aligned base contact comprising: providing an emitter disposed on a base; forming a T-shaped mold on top of the emitter; and forming a T-shaped emitter contact within the T-shaped mold and on top of the emitter, wherein the T-shaped emitter contact comprises a first portion and a second portion, the first portion contacting the emitter, and the second portion extending laterally beyond the emitter; and disposing one or more base contacts on the base after forming said T-shaped emitter contact; wherein forming the T-shaped mold comprises: providing a first and second layer of electron sensitive resist on the emitter; forming a mold for the first portion in the first layer of electron sensitive resist; forming a mold for the second portion in the second layer of electron sensitive resist, and wherein forming the T-shaped emitter contact comprises: evaporating metal in the T-shaped mold.