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Browse Prior Art Database

High Temperature Epitaxial Pre-Bake Process

IP.com Disclosure Number: IPCOM000049889D
Original Publication Date: 1982-Aug-01
Included in the Prior Art Database: 2005-Feb-09
Document File: 1 page(s) / 11K

Publishing Venue

IBM

Related People

Basso, JE: AUTHOR [+2]

Abstract

The pre-bake process used prior to growing 2-micron epitaxy on buried high concentration arsenic diffused sub-collectors is critical. It has been demonstrated that leakage-limited yield sensitivities are directly related to the epitaxy pre-6ake temperature for standard bake times.

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High Temperature Epitaxial Pre-Bake Process

The pre-bake process used prior to growing 2-micron epitaxy on buried high concentration arsenic diffused sub-collectors is critical. It has been demonstrated that leakage-limited yield sensitivities are directly related to the epitaxy pre-6ake temperature for standard bake times.

Pre-baking at 1175 degrees +/- 5 degrees C for approximately 20 minutes prior to growing epitaxy at 1150 degrees +/- 5 degrees C on buried subcollectors with concentration greater than 10/20/ per cu cm eliminates prismatic dislocation loops resulting from the high concentration of arsenic at the sub-collector epitaxy interface. These dislocations migrate during subsequent processing and can intersect emitter and base to form a pipe defect. This has been shown to significantly impact LSI (large-scale integration) circuit yields.

The proposed high temperature pre-bake process consists of slow heating of the wafers from ambient to 900 degrees C in 0 to 5 minutes; heating 900 degrees to 1175 degrees C in approximately 2 minutes; and baking at 1175 degrees C for 18 +/- 1 minute. The temperature is then lowered from 1175 degrees to 1150 degrees C for a standard SiCL(4) epitaxial deposition.

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