Reacted conductive gate electrodes and methods of making the same

A method comprising:

• forming a strained channel layer over a substrate, the substrate comprising a relaxed region, the relaxed region comprising a first material and a second material;
• forming a gate structure over the strained channel layer, the gate structure comprising a contact with a graded composition of the first material and the second material;
• and
• reacting a portion of the relaxed region and a portion of the contact with a metal in a single process step to form a reacted contact on the relaxed region and on the contact.

A method for fabricating a semiconductor device, comprising:

• providing a relaxed semiconductor layer comprising a first material and a second material;
• forming a gate structure over the relaxed semiconductor layer, the gate structure comprising a contact comprising a first portion proximal to the relaxed semiconductor layer and a second portion distal to the relaxed semiconductor layer, the second portion comprising the first material and the second material;
• and
• simultaneously reacting a metal with the relaxed semiconductor layer and with the second portion of the contact.