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Surface Treatment During Transistor Fabrication

IP.com Disclosure Number: IPCOM000091389D
Original Publication Date: 1968-Jan-01
Included in the Prior Art Database: 2005-Mar-05
Document File: 1 page(s) / 11K

Publishing Venue

IBM

Related People

Fink, MS: AUTHOR

Abstract

A noble metal contact system for high-speed transistors includes electroless Pd on Pt-Si. However, the Pt deposition and alloying result in the formation of a carbon containing residue on the thermal oxide and platinum-silicide surface. This leads to high contact resistance and poor adhesion.

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Surface Treatment During Transistor Fabrication

A noble metal contact system for high-speed transistors includes electroless Pd on Pt-Si. However, the Pt deposition and alloying result in the formation of a carbon containing residue on the thermal oxide and platinum-silicide surface. This leads to high contact resistance and poor adhesion.

To overcome this problem, after Pt-Si formation, but before Pd deposition, the following procedure is followed to remove the carbon residue.

1. Oxidize the carbon residue, as by immersion in a hot oxidation solution or by burning. This leaves another residue of silicon oxide, but only on the surface of the platinum silicide.

2. Remove the silicon oxide residue by ultrasonic etching in a NH(4)H(2)PO(4) solution.

The residue is removed in about two minutes and adherent low resistance palladium can then be electrolessly plated.

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