Browse Prior Art Database

Contact Barrier Metallurgy for MOSFET Gate

IP.com Disclosure Number: IPCOM000087528D
Original Publication Date: 1977-Feb-01
Included in the Prior Art Database: 2005-Mar-03
Document File: 1 page(s) / 11K

Publishing Venue

IBM

Related People

Garbarino, PL: AUTHOR [+3]

Abstract

In a self-aligned gate contact structure, aluminum (Al) metal lines are put directly in contact with the device poly-silicon (poly-Si) crystalline gate. The problem of dissolution of the poly-Si gate by the overlay Al line is encountered even if the Al line contains Si to its solubility limit. The advantages of using the poly-Si gate may thus be lost.

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Contact Barrier Metallurgy for MOSFET Gate

In a self-aligned gate contact structure, aluminum (Al) metal lines are put directly in contact with the device poly-silicon (poly-Si) crystalline gate. The problem of dissolution of the poly-Si gate by the overlay Al line is encountered even if the Al line contains Si to its solubility limit. The advantages of using the poly-Si gate may thus be lost.

A metallurgy system consisting of a metal silicide layer as the contact barrier and the Si-doped Al as conduction metallurgy overcomes this problem. The metal silicide is formed after the construction of the device gate by deposition of a layer of metal film of predetermined thickness which depends upon the desired silicide thickness, and followed by a proper silicide-forming heat treatment. The silicides suitable for this purpose are those formed at relatively high temperature (400-800 Degrees C). Their formation rate is controlled by Si diffusion in the silicide-forming metal, e.g., silicides of platinum, nickel, hafnium, tantalum and palladium.

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