Heterojunction bipolar transistor with buried selective sub-collector layer, and methods of manufacture

US5981985A · kind A · utility

Assignee

• The Trustees of Columbia University in the City of New York · US

Inventors

• Yue Yang · Chengdu, CN
• Edward S. Yang · Armonk, US

Key dates

• Filing date: Jun 24, 1996
• Grant date: Nov 9, 1999
• Expiry date: Jun 24, 2016

Classification

• Technology area (CPC H): Electricity
• CPC primary: H10D62/85

Abstract

In an integrated heterojunction bipolar transistor (HBT) with minimized base-collector capacitance, a sub-collector region is formed as a mesa on a substrate, a collector contact is to the sub-collector mesa region, a lightly-doped collector region and a base region extend from the mesa onto the substrate, and a base contact and its via hole for interconnection are off the mesa, with minimal overlap with the sub-collector region. The latter may be termed a buried selective sub-collector (BSSC) region. Such transistors can be used as integrated switching devices and microwave devices, e.g., in wireless communications, satellite direct broadcast systems, automobile collision avoidance systems, global positioning systems, and other high-frequency applications.