US Patent 9786656 Integration of bipolar transistor into complimentary metal-oxide-semiconductor process

A fin heterojunction bipolar transistor (fin HBT) and a method of fabricating the fin HBT for integration with a fin complimentary metal-oxide-semiconductor (fin CMOS) into a BiCMOS fin device include forming a sub-collector layer on a substrate. The sub-collector layer includes silicon doped with arsenic (As+). A collector layer and base are patterned as fins along a first direction. An emitter layer is formed on the fins. The emitter layer is a continuous layer of epitaxially grown silicon. An oxide is deposited above the sub-collector layer, the base, and the emitter layer, and at least one contact is formed through the oxide to each of the sub-collector layer, the base, and the emitter layer.