Method of producing a Si-Ge base heterojunction bipolar device

US6559021B2 · kind B2 · utility

Assignee

• SiGe Semiconductor, Inc. · CA

Inventors

• Derek C. Houghton · Ottawa, CA
• Hugues Lafontaine · Ottawa, CA

Key dates

• Filing date: Nov 20, 2001
• Grant date: May 6, 2003
• Expiry date: Nov 20, 2021

Classification

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

Abstract

A method of producing a bipolar transistor includes the step of providing a sacrificial mesa over a layer of SiGe in order to prevent a polysilicon covering layer from forming over a predetermined region of the SiGe layer forming the transistor base. After an etching process removes the sacrificial mesa and the SiGe layer is exposed, an oppositely doped material is applied over top of the SiGe layer to form an emitter. This makes it possible to realize a thin layer of silicon germanium to serve as the transistor base. This method prevents the base layer SiGe from being affected, as it otherwise would be using a conventional double-poly process.