Browse Prior Art Database

Semiconductor Process Control

IP.com Disclosure Number: IPCOM000091941D
Original Publication Date: 1968-Jul-01
Included in the Prior Art Database: 2005-Mar-05
Document File: 2 page(s) / 27K

Publishing Venue

IBM

Related People

Lloyd, RH: AUTHOR

Abstract

In semiconductor devices having buried collector regions, emitter diffusion is used to control the base diffusion into the buried collector region. The amount of base diffusion can be monitored by measuring the base-collector breakdown voltage.

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Semiconductor Process Control

In semiconductor devices having buried collector regions, emitter diffusion is used to control the base diffusion into the buried collector region. The amount of base diffusion can be monitored by measuring the base-collector breakdown voltage.

A slab of semiconductor material 10 has collector region 12 diffused in it from one surface. Base region 14 is diffused into material 10 from the other surface. Emitter region 16 is subsequently formed by another diffusion and that diffusion is into the base region 14. This diffusion of emitter region 16 results in bulge 18 in base region 14. Bulge 18 extends into buried collector region 12. Lastly, contacts 18, 20, 22, and 24 are formed on the various regions of semiconductor
10.

After the diffusion of emitter region 16, a voltage is applied across the junction of base region 14 and collector 12. Through empirical relationships, the penetration of the bulge 18 into region 12 can be determined by measuring the base-collector breakdown voltage. Thus, that voltage can be used to monitor the emitter diffusion. The base width under emitter region 16 can be concurrently monitored by measuring the collector-emitter breakdown voltage with the base open. This is because such voltage is dependent on the base width and the penetration into region 12.

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