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:
Dec. 12, 2000
Filed:
Feb. 06, 1998
Jon Cheek, Round Rock, TX (US);
William A Whigham, Austin, TX (US);
Derick Wristers, Austin, TX (US);
Advanced Micro Devices, Inc., Sunnyvale, CA (US);
Abstract
A method for slowing the diffusion of boron ions in a CMOS structure includes a preanneal step which can be incorporated as part of a step in which silane is deposited across the surface of the wafer. After the last implant on a CMOS device, silane (SiH.sub.4) is deposited over the surface of the wafer using a chemical vapor deposition (CVD) tool. The deposition of silane is done at 400.degree. C. The temperature is raised in the CVD tool to a temperature in the range of 550.degree. C. to 650.degree. C. and held for 30-60 minutes. This temperature does not affect the thin film of silicon which is formed from the silane, yet provides the necessary thermal cycle to 'repair' the crucial first 200 .ANG. to 600 .ANG. of the silicon surface. Normal processing steps, including a rapid thermal anneal for 30 seconds at 1025.degree. C. follow. The RTA is necessary to activate the dopants (arsenic and boron) in the source and drain of the respective devices. The boron dopant species diffuses less during subsequent rapid thermal anneal cycles since the crucial first 200 .ANG. to 600 .ANG. of the silicon surface have been repaired using this preanneal step.