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:
Jun. 29, 2004
Filed:
Feb. 01, 2002
Stephen J. Kovacic, Ottawa, CA;
Derek C. Houghton, Gloucester, CA;
SiGe Semiconductor Inc., Ottawa, CA;
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.