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Metal-diffusion Barrier Composite in the Polycide Process

IP.com Disclosure Number: IPCOM000060633D
Original Publication Date: 1986-Mar-01
Included in the Prior Art Database: 2005-Mar-09
Document File: 1 page(s) / 11K

Publishing Venue

IBM

Related People

Ahn, KY: AUTHOR [+4]

Abstract

A thin metal and nitride composite underlayer can be used as a metal-diffusion barrier in the polycide process. The thin nitride layer maintains adhesion and resistivity and acts as a diffusion barrier for a dopant and silicon in the polysilicon layer during source/drain oxidation. The thin metal layer lowers the resistivity of the composite and promotes the adhesion of silicide to the nitride.

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Metal-diffusion Barrier Composite in the Polycide Process

A thin metal and nitride composite underlayer can be used as a metal- diffusion barrier in the polycide process. The thin nitride layer maintains adhesion and resistivity and acts as a diffusion barrier for a dopant and silicon in the polysilicon layer during source/drain oxidation. The thin metal layer lowers the resistivity of the composite and promotes the adhesion of silicide to the nitride.

The metal diffusion barrier is applied by deposition of a thin conducting nitride (TIN), on the polysilicon substrate by either evaporation sputtering or chemical vapor deposition. A pure metal (i.e., titanium, cobalt, platinum etc.) having a thickness of 150-200 Angstroms is then deposited on the nitride. Finally, tungsten silicide is deposited on the composite metal nitride structure. The whole layered structure is then annealed and patterned or patterned and annealed as is required. The presence of the underlying titanium or cobalt nucleation of the tungsten silicide and a very thin metal-silicon bond is formed between the silicide and the metal.

Disclosed anonymously.

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