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:
Sep. 03, 1991
Filed:
Aug. 30, 1988
Min-Liang Chen, Lower Macungie Township, Lehigh County, PA (US);
William T Cochran, Lynn Township, Lehigh County, PA (US);
Chung W Leung, South Whitehall Township, Lehigh County, PA (US);
AT&T Bell Laboratories, Murray Hill, NJ (US);
Abstract
A p-type tub in a CMOS integrated circuit is isolated from the adjacent n-type tub by means of a field oxide having a p-type channel stop region formed by a boron ion implant. The depth of the ion implant is selected so that the peak of the boron concentration is located immediately under the field oxide region that is subsequently grown. In addition, the implant is allowed to penetrate into the active device regions, producing a retrograde boron concentration in the n-channel region. This technique simultaneously improves device isolation and n-channel transistor punch-through characteristics, allowing the extension of CMOS technology to sub-micron device geometries.