Si-Ge base heterojunction bipolar device

US6756604B2 · kind B2 · utility

Assignee

• SiGe Semiconductor, Inc. · CA

Inventors

• Stephen Joseph Kovacic · Ottawa, CA
• Derek C. Houghton · Ottawa, CA

Key dates

• Filing date: Feb 1, 2002
• Grant date: Jun 29, 2004
• Expiry date: Feb 1, 2022

Classification

• Technology area (CPC H): Electricity
• CPC primary: H10D10/891

Abstract

A bipolar transistor is disclosed that is produced using a sacrificial mesa disposed over a layer of Si and SiGe in order to prevent a polysilicon covering layer from forming over a predetermined region of the Si and SiGe layer forming the transistor base. After an etching process, the sacrificial mesa is removed and the Si and SiGe layer is exposed, where an oppositely doped material is applied over top of the Si and SiGe layer to form an emitter. This makes it possible to realize a thin layer of Si and silicon germanium to serve as the transistor base. The transistor device formed using the sacrificial mesa results in the base layer Si and SiGe not being affected by a process of etching, as it otherwise would be using a conventional double-poly process, which results in a more repeatable bipolar transistor device yield.