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:
May. 21, 2002
Filed:
Apr. 04, 2000
Ming-Tsung Tung, Hsin-Chu, TW;
United Microelectronics Corp., Hsin-Chu, TW;
Abstract
A method for fabricating an HVMOS transistor that can reduce snapback is disclosed. The semiconductor wafer comprises an N-type silicon substrate, and a P-type epitaxial layer formed on the surface of the silicon substrate. The HVMOS transistor comprises a first P-well region formed within the epitaxial layer, a second P-well region formed within the first P-well region a source region formed within the second P-well region, an N-drain region formed in the epitaxial layer, a gate, and an N-type diffused region formed both in the epitaxial layer and in the silicon substrate. The diffused region is under the first P-well region and overlaps the first P-well region.