Patent ID: 6894362
Filing Date: 2005-05-17
Classification: H01L

Abstract:
1. A compound semiconductor Heterojunction Bipolar Transistor (HBT) device, said HBT device comprising: a compound semiconductor substrate, wherein said substrate comprises at least one base layer, and an emitter mesa having at least one emitter layer and at least one etch stop layer; an emitter contact formed on said emitter mesa of said substrate such that said emitter contact is not undercut; a base contact formed on said base layer of said substrate to establish a low resistance contact between said base contact and said substrate; a collector contact formed on an uncoated region of said substrate; at least one dielectric covering layer; and a planarization film; wherein said emitter mesa is formed by covering said emitter contact with a first dielectric film to create dielectric sidewalls which serve as an etch mask for forming said emitter mesa under said emitter contact; wherein said base contact and said emitter contact are self-aligned; wherein said HBT is coated with a second dielectric film encapsulating said emitter, base and collector contacts; wherein said HBT is planarized with said planarization film; and wherein said emitter, base, and collector contacts of said HBT are exposed by etching said planarization film to facilitate device interconnection.