Very low pressure chemical vapor deposition process for deposition of titanium silicide films

Claim 1

The method of forming titanium silicide over selected regions of a substrate patterned with exposed oxide regions and silicon regions in a low pressure chemical vapor deposition chamber comprising the steps of: (a) from a Si containing reactant gas depositing a thin layer of silicon over said exposed regions; (b) from Si and Ti containing reactant gasses promptly thereafter depositing titanium silicide for a period of time which initially results in substantial consumption of the thin silicon layer, thereby exposing said oxide regions and continuing said deposition to form titanium silicide only over the silicon regions and not over the now exposed oxide regions with the silicon for the continued deposition of titanium silicide being supplied primarily by the Si containing reactant.

Claim 2

The method of forming titanium silicide over selected regions of a substrate patterned with exposed oxide regions and silicon regions in a low pressure chemical vapor deposition chamber comprising the steps of: (a) from a Si containing reactant gas depositing a thin layer of silicon over said exposed regions; (b) from Si and Ti containing reactant gasses promptly thereafter depositing titanium silicide for a period of time which initially results in substantial consumption of the thin silicon layer, thereby exposing said oxide regions and continuing said deposition to form titanium silicide only over the silicon regions and not over the now exposed oxide regions with the silicon for the continued deposition of titanium silicide being supplied primarily by the Si containing reactant.

Claim 8

The method of forming titanium silicide over selected regions of a substrate patterned with exposed oxide regions and silicon regions in a chemical vapor deposition chamber comprising the steps of: (a) establishing a very low pressure condition in said chamber of about 67 mTorr, or less, from a gaseous silicon halide and depositing a thin layer of silicon over said exposed oxide regions and silicon regions at a substrate deposition temperature of about 600° C.; (b) from a gaseous silicon halide and a gaseous titanium halide promptly thereafter depositing titanium silicide at a substrate temperature of about 730° C. for a period of time which results in consumption of the thin layer of silicon, thereby re-exposing said oxide regions and continuing said deposition to form titanium silicide only over the silicon regions with the silicon for the continued deposition of titanium silicide being supplied from the gaseous silicon halide without substantial consumption of the remaining silicon in the silicon regions.

Claim 9

The method of forming titanium silicide over selected regions of a substrate patterned with exposed oxide regions and silicon regions in a chemical vapor deposition chamber comprising the steps of: (a) establishing a very low pressure condition in said chamber of about 67 mTorr, or less, from a gaseous silicon halide and depositing a thin layer of silicon over said exposed oxide regions and silicon regions at a substrate deposition temperature of about 600° C.; (b) from a gaseous silicon halide and a gaseous titanium halide promptly thereafter depositing titanium silicide at a substrate temperature of about 730° C. for a period of time which results in consumption of the thin layer of silicon, thereby re-exposing said oxide regions and continuing said deposition to form titanium silicide only over the silicon regions with the silicon for the continued deposition of titanium silicide being supplied from the gaseous silicon halide without substantial consumption of the remaining silicon in the silicon regions.

Claim 13

A method of selectively forming titanium silicide in-situ over silicon regions of a patterned substrate in a cold walled reactor comprising the steps of: (a) mounting a substrate having patterned regions comprising exposed oxide regions and exposed silicon regions on a holder in the reactor; (b) bringing the pressure in the reactor to a relatively low pressure of about 67 mTorr, or less; (c) selectively heating the substrate with radiant thermal energy to bring the substrate to a predetermined temperature of about 600° C. at which formation of a silicon film from a known reactant will occur on the substrate; while keeping the reactor walls at a substantially lower temperature; (d) introducing a gaseous silicon atom containing reactant into the reactor to form a thin polysilicon layer on the patterned substrate; (e) promptly selectively heating the substrate and polysilicon layer by radiant thermal energy to bring the substrate and thin polysilicon layer to a predetermined temperature of about 730 ° C. suitable for formation of a titanium silicide layer while maintaining the reactor walls at a substantially lower temperature; (f) introducing a gaseous silicon atom containing reactant and a gaseous titanium atom containing reactant into the reactor to from a layer of titanium silicide only over the silicon regions by initially consuming the thin polysilicon layer until the oxide regions are once again exposed and continuing the reaction until the titanium silicide is formed only over the silicon regions by supplying silicon for the continuing formation from the gaseous silicon atom containing reactant without further substantial consumption of the remaining silicon in the silicon regions.

Claim 14

A method of selectively forming titanium silicide in-situ over silicon regions of a patterned substrate in a cold walled reactor comprising the steps of: (a) mounting a substrate having patterned regions comprising exposed oxide regions and exposed silicon regions on a holder in the reactor; (b) bringing the pressure in the reactor to a relatively low pressure of about 67 mTorr, or less; (c) selectively heating the substrate with radiant thermal energy to bring the substrate to a predetermined temperature of about 600° C. at which formation of a silicon film from a known reactant will occur on the substrate; while keeping the reactor walls at a substantially lower temperature; (d) introducing a gaseous silicon atom containing reactant into the reactor to form a thin polysilicon layer on the patterned substrate; (e) promptly selectively heating the substrate and polysilicon layer by radiant thermal energy to bring the substrate and thin polysilicon layer to a predetermined temperature of about 730 ° C. suitable for formation of a titanium silicide layer while maintaining the reactor walls at a substantially lower temperature; (f) introducing a gaseous silicon atom containing reactant and a gaseous titanium atom containing reactant into the reactor to from a layer of titanium silicide only over the silicon regions by initially consuming the thin polysilicon layer until the oxide regions are once again exposed and continuing the reaction until the titanium silicide is formed only over the silicon regions by supplying silicon for the continuing formation from the gaseous silicon atom containing reactant without further substantial consumption of the remaining silicon in the silicon regions.