Method for device metallization by forming a contact plug and interconnect using a silicide/nitride process

A method for fabricating a semiconductor device, comprising the steps of:

• providing a silicon substrate;
• forming a device region at the surface of said substrate;
• forming an insulating layer overlying said surface;
• forming an opening through said insulating layer to expose a portion of said device region;
• sequentially sputter depositing a layer of titanium overlying said insulating layer and extending into said opening to contact said portion of said device region in an inert and
• a layer of tungsten to overlie and contact said layer of titanium in a sputtering apparatus, wherein said sequential sputtering is performed without exposing the sputtered layers to room ambient;
• heating in a nitrogen containing ambient and diffusing nitrogen atoms through said sputtered tungsten layer to form titanium silicide at the silicon-titanium interface and titanium nitride at the titanium-tungsten interface;
• chemical vapor depositing tungsten overlying said layer of sputtered tungsten to a thickness sufficient to substantially fill said opening;
• etching back said chemical vapor deposited tungsten to remove substantially all of same overlying said insulator, to expose portions of said layer of titanium, and to leave said chemical vapor deposited tungsten substantially filling said opening;
• applying a layer comprising aluminum to contact said chemical vapor deposited tungsten remaining in said openings;
• and
• selectively patterning said layer comprising aluminum and any titanium remaining thereunder.