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Method for Gettering an Oxide Film On the Surface of a Polysilicon Layer

IP.com Disclosure Number: IPCOM000060101D
Original Publication Date: 1986-Feb-01
Included in the Prior Art Database: 2005-Mar-08
Document File: 1 page(s) / 12K

Publishing Venue

IBM

Related People

Hallock, DP: AUTHOR [+6]

Abstract

This article discloses a method of forming a polycide gate structure whereby a thin layer of titanium or titanium disilicide is deposited on the surface of a polysilicon layer just prior to the deposition of a silicide layer. The method eliminates the thin, native oxide layer present on the surface of the polysilicon layer, thereby improving adhesion of the silicide layer.

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Method for Gettering an Oxide Film On the Surface of a Polysilicon Layer

This article discloses a method of forming a polycide gate structure whereby a thin layer of titanium or titanium disilicide is deposited on the surface of a polysilicon layer just prior to the deposition of a silicide layer. The method eliminates the thin, native oxide layer present on the surface of the polysilicon layer, thereby improving adhesion of the silicide layer.

Referring to the figure, silicon substrate 11 is provided with gate oxide layer
12. Polysilicon layer 13 is deposited on the surface of gate oxide layer 12. A thin layer of titanium or titanium disilicide 16 is then deposited on the surface of polysilicon layer 13 by evaporation. Next, tungsten silicide layer 14 is deposited on the surface of the layer 16 by co- evaporating tungsten and silicon. Sputtering may also be used for the deposition of titanium and tungsten silicide. Finally, the entire structure is sintered. Other refractory metal silicides, such as titanium silicide, tantalum silicide, and molybdenum silicide, may be used instead of tungsten silic

Due to the strong affinity of titanium for oxygen, the titanium layer acts to getter non-uniform native oxide and prevent subsequent silicon atom movement at the surface of polysilicon layer 13. Voids are thus eliminated in the final structure, thereby improving adhesion of tungsten silicide layer 14 to polysilicon layer 13 and reducing the likelihood of delamination....