Semiconductor device and method for forming the device using a dual layer, self-aligned silicide to enhance contact performance

A method for forming a silicide, comprising:

• providing a source region and a drain region spaced from each other by a gate conductor;
• depositing a layer of titanium upon the source and drain regions and the gate conductor;
• annealing the layer of titanium partially into the source and drain regions and into the gate conductor;
• depositing a layer of cobalt upon the annealed said layer of titanium;
• and
• annealing the layer of cobalt partially into the source and drain regions and into the gate conductor.

A method for forming a silicide, comprising:

• providing a source region and a drain region spaced from said source region by a gate conductor;
• depositing a layer of titanium upon the source and drain regions and the gate conductor;
• depositing a layer of cobalt upon the layer of titanium;
• and
• interdiffusing the source and drain regions with the layers of cobalt and titanium at a temperature sufficient to form XSi.sub.Y, where X consists of titanium or cobalt and where Y is less than two.