Mosfets incorporating nickel germanosilicided gate and methods for their formation

A metal oxide semiconductor field effect transistor (MOSFET) device, comprising:

• a semiconductor substrate comprising a layer of silicon germanium;
• source and drain regions formed in the silicon germanium layer;
• a strained silicon channel region formed on the silicon germanium layer and extending between the source and drain regions;
• a gate insulator overlying the channel region;
• and
• nickel germanosilicide contacts formed on the silicon germanium source and drain regions.

A process for forming a metal oxide semiconductor field effect transistor (MOSFET), comprising:

• providing a s miconductor comprising a layer of silicon germanium, a surface layer of strained silicon overlying the layer of silicon germanium, a gate insulating layer formed on the strained silicon, and a gate conductive layer formed on the gate insulating layer;
• patterning the gate conductive layer to form a gat overlying the gate insulating layer;
• removing the strained silicon layer from source and drain regions of the MOSFET to form a strained silicon channel region of the MOSFET,
• forming a layer of nickel in contact with the silicon germanium layer in the source and drain regions;
• and
• performing thermal treatment to form nickel germanosilicide contacts on the silicon germanium source and drain regions.