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:
Nov. 05, 2002
Filed:
Jul. 23, 2001
Chih-Feng Huang, Chu-Pei, TW;
Kuo-Su Huang, Hsin-Chu, TW;
Taiwan Semiconductor Manufacturing Company, Hsin-Chu, TW;
Abstract
P-type LDMOS devices have been difficult to integrate with N-type LDMOS devices without adding an extra mask because the former have been unable to achieve the same breakdown voltage as the latter due to early punch-through. This problem has been overcome by preceding the epitaxial deposition of N− silicon onto the P− substrate with an additional process step in which a buried N+ layer is formed at the surface of the substrate by ion implantation. This N+ buried layer significantly reduces the width of the depletion layer that extends outwards from the P− well when voltage is applied to the drain thus substantially raising the punch-through voltage.