The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Dec. 16, 1997
Filed:
Jun. 07, 1995
Jau-Yuann Yang, Richardson, TX (US);
Donald L Plumton, Dallas, TX (US);
Francis J Morris, Plano, TX (US);
Texas Instruments Incorporated, Dallas, TX (US);
Abstract
A self-aligned planar heterojunction bipolar transistor (10) is fabricated by forming a base layer (18) and forming an emitter layer (20) on the base layer (18). An emitter cap layer (22) is formed on the emitter layer (20) and an interface layer (24) is formed on the emitter cap layer (22). A first implantation layer (26) is formed through the interface layer (24), the emitter cap layer (22), and the emitter layer (20) to the base layer (18). A second implantation layer (30) is formed through the interface layer (24), the emitter cap layer (22), and the emitter layer (20) to the base layer (18) and overlaps the first implantation layer (26). A portion of the interface layer (24), the emitter cap layer (22), and the implantation layers (26, 30) are removed and replaced by an insulating region (33). An emitter contact (38) is formed on the remaining emitter cap layer (22) and is isolated from the implantation layers (26, 30) by the insulating region (33). The insulating region (33) acts as a buffer to self-align the emitter contact (38) to the implantation layer (26, 30).