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:
Feb. 03, 2009
Filed:
Mar. 27, 2006
Jamal Ramdani, Scarborough, ME (US);
Craig Richard Printy, Buxton, ME (US);
Jamal Ramdani, Scarborough, ME (US);
Craig Richard Printy, Buxton, ME (US);
National Semiconductor Corporation, Santa Clara, CA (US);
Abstract
A base structure for high performance Silicon Germanium (SiGe) based heterojunction bipolar transistors (HBTs) with arsenic atomic layer doping (ALD) is disclosed. The ALD process subjects the base substrate to nitrogen gas or hydrogen gas (in ambient temperature approximately equal to 500 degrees Celsius) and provides an additional SiGe spacer layer. The surface of the final silicon cap layer is preferably etched to remove most of the arsenic. The resulting SiGe HBT with an arsenic ALD layer is less sensitive to process temperature and exposure times, and exhibits lower dopant segregation and sharper base profiles.