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:
Jun. 08, 2004
Filed:
Sep. 25, 2002
Sandhya Gupta, Bloomington, MN (US);
Steve L. Kosier, Lakeville, MN (US);
John C. Beckman, Minneapolis, MN (US);
PolarFab LLC, Bloomington, MN (US);
Abstract
An integrated circuit having very low parasitic current gain includes a guard ring that is used to completely surround a device, such as a power device, that induces parasitic current. The guard ring is formed in a semiconductor body layer such as an epitaxial layer and has a central guard ring of the same type conductivity as that of the body layer and additional flanking rings of the opposite type conductivity. An unbiased configuration of the guard ring based on the above structure is particularly effective in reducing the parasitic gain. The effectiveness of the guard ring, such as the high current performance, is further improved by reducing the resistance between neighboring rings using various methods.