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Gettering Technique

IP.com Disclosure Number: IPCOM000078057D
Original Publication Date: 1972-Nov-01
Included in the Prior Art Database: 2005-Feb-25
Document File: 1 page(s) / 11K

Publishing Venue

IBM

Related People

Keenan, WA: AUTHOR [+3]

Abstract

In this gettering technique, high-impurity concentrations diffused regions are provided to immobilize metallic impurities within a semiconductor device, before they react with any dissociated device diffusions.

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Gettering Technique

In this gettering technique, high-impurity concentrations diffused regions are provided to immobilize metallic impurities within a semiconductor device, before they react with any dissociated device diffusions.

The periphery of a semiconductor wafer has normally a high-dislocation density and a high stress. Metallic impurities introduced during fabrication of the device interact with dislocations, causing low-breakdown voltage and high leakage in the subsequent devices, reducing the quality of the devices and also the yield.

In this technique, the ring diffusion extending about the periphery of the wafer is provided to getter metallic impurities present in the wafer or introduced during processing. The gettering ring is a diffusion made at the same time the isolation or subregion diffusions are made in the wafer, about the edge utilizing the area outside the normal device pattern along the periphery of the wafer. Preferably, the diffusion is also made to the backside of the wafer. Subsequently, the epitaxial layer is deposited and the devices completed utilizing normal fabrication techniques.

The gettering ring diffusion minimizes the interaction of metallic impurities and crystalline perfections, such as copper and gold, which are always present in silicon wafers during fabrication of the devices and which would ordinarily result in numerous internal shorts.

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