Browse Prior Art Database

Shallow Guard Ring Process for Reach Through Guard Ring Products

IP.com Disclosure Number: IPCOM000045827D
Original Publication Date: 1983-Apr-01
Included in the Prior Art Database: 2005-Feb-07
Document File: 1 page(s) / 11K

Publishing Venue

IBM

Related People

Cooper, SA: AUTHOR [+2]

Abstract

The present process to eliminate p-region to p-region (P-P) leakage is the diffused guard ring.

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This is the abbreviated version, containing approximately 100% of the total text.

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Shallow Guard Ring Process for Reach Through Guard Ring Products

The present process to eliminate p-region to p-region (P-P) leakage is the diffused guard ring.

This guard ring is diffused from the epitaxial surface through to the buried subcollector. This guard ring is about as wide as the epitaxial layer is thick. While this doesn't present a problem on low circuit density products, the higher the circuit density becomes the more critical is the spacing. The most critical is the resistor to resistor and the resistor to isolation spacing. Thus, a process was developed to diffuse a shallow guard ring structure. The shallow structure will eliminate the P-P leakage and allow tighter spacing between resistor and isolation.

The shallow guard ring process will eliminate several problems.

It eliminates P-P leakage by protecting the epitaxial surface from inversion. It allows for good circuit density when compared to the reach-through guard ring process. Thus, chip size can be reduced and more chips can be placed on a wafer.

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