Process for forming self-aligned titanium silicide by heating in an oxygen rich environment

A process for producing a semiconductor device comprising:

• providing a silicon substrate;
• forming doped source and drain regions in said substrate, a polysilicon gate region separated rom said substrate by a gate oxide layer, insulating spacer regions adjacent to sidewalls of said gate region, and lightly doped source and drain regions in said substrate below said spacer regions;
• forming a titanium layer overlying said source, drain, gate and sidewall regions;
• heating said device above 580 degrees C. in an oxygen rich environment to form titanium silicide overlying said source, drain and gate regions thereby reducing their electrical resistance, and to form titanium oxide overlying said spacer regions and titanium silicide thereby electrically insulating the underlying titanium silicide;
• forming an electrically insulating layer over said titanium oxide;
• opening windows in said insulating layer and titanium oxide;
• and
• forming metal in said windows to provide electrical contact to said titanium silicide.

A process for forming self-aligned metal silicide layers over source, drain and gate regions of a MOS semiconductor device comprising:

• providing a silicon substrate;
• forming field oxide regions to bound said source, drain and gate regions;
• forming a gate oxide on said substrate;
• forming a polysilicon gate region on said gate oxide;
• lightly doping said substrate underlying said gate oxide and between said gate and field oxide regions to define low dopant drain/source (LDD) regions and to define said source and drain regions;
• forming spacer oxide regions on the sidewalls of said gate region and overlying said LDD regions, removing said gate oxide adjacent said sidewalls and overlying said source and drain regions, and further doping said source and drain regions;
• depositing a metal layer on said device;
• and
• heating said device in an oxygen rich environment to form metal silicide overlying said source, drain and gate regions and to form metal oxide overlying said metal silicide and said field and spacer oxide regions;
• and
• forming an electrically insulating layer over said metal oxide.

A process for producing a semiconductor device comprising:

• forming a metal layer over silicon and insulator regions;
• heating said layer in an oxygen rich environment to form:
• metal silicide over said silicon region;
• and
• metal oxide over said insulator region and metal silicide;
• and
• selectively removing some but not all of the metal oxide which is over said metal silicide.