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Flash Evaporated Al Si Contacts for SLT Devices

IP.com Disclosure Number: IPCOM000095189D
Original Publication Date: 1965-Oct-01
Included in the Prior Art Database: 2005-Mar-07
Document File: 1 page(s) / 11K

Publishing Venue

IBM

Related People

Totta, PA: AUTHOR

Abstract

Aluminum-silicon alloy contacts for planar transistors have the advantage that such a device can be heated for glass passivation purposes to a temperature as high as 575 degrees C. Such occurs without any aluminum penetration into the silicon substrate.

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Flash Evaporated Al Si Contacts for SLT Devices

Aluminum-silicon alloy contacts for planar transistors have the advantage that such a device can be heated for glass passivation purposes to a temperature as high as 575 degrees C. Such occurs without any aluminum penetration into the silicon substrate.

A thin film of aluminum is first deposited on the silicon wafer. Then a film of aluminum-silicon is deposited over it. The latter alloy supplies any affinity of aluminum for silicon. Any excess aluminum-silicon alloy can be subtractively etched by placement in an ultrasonic bath. No subsequent mechanical cleaning is necessary.

The particular process includes a step of flash-evaporating pure aluminum on the silicon wafer to the thickness of 500 to 1000 angstroms at about 300 degrees
C. This is followed by a second flash evaporation step of aluminum and silicon to a thickness of 4000-6000 angstroms. The silicon content in the second step is between 1. 5% and 6%.

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