Inducing channel strain via encapsulated silicide formation

A method of forming a semiconductor structure, the method comprising:

• forming a transistor structure including a gate on a semiconductor substrate, a channel region in the semiconductor substrate below the gate, and a source/drain region in the semiconductor substrate adjacent to the channel region;
• forming a metal-rich silicide layer on at least a portion of a top surface of the source/drain region;
• depositing a interlevel dielectric layer above the transistor structure;
• etching the interlevel dielectric layer form a contact recess, wherein the contact recess exposes a portion of the metal-rich silicide layer;
• forming a metal contact in the contact recess region, wherein the metal-rich silicide layer is encapsulated by the formation of the metal contact;
• and
• converting the metal-rich silicide layer to a silicon-rich silicide layer, wherein silicon-rich silicide layer applies tensile or compressive stress to the channel region, wherein the silicon-rich silicide layer remains encapsulated by the metal contact after converting the metal-rich silicide layer to a silicon-rich silicide layer.

A method of forming a semiconductor structure, the method comprising:

• forming a transistor structure including a gate on a semiconductor substrate, a channel region in the semiconductor substrate below the gate, and a source/drain region in the semiconductor substrate adjacent to the channel region;
• depositing a interlevel dielectric layer above the transistor structure;
• etching the interlevel dielectric layer form a contact recess, wherein the contact recess exposes a portion of the source/drain region;
• forming a metal liner in the contact recess region, wherein the metal liner is on the exposed portion of the source/drain region;
• forming a metal fill in the contact recess region wherein the metal fill encapsulates the metal liner and the exposed portion of the source/drain region;
• and
• forming a silicide layer on the source/drain region by reacting a portion of the metal liner with a portion of the source/drain region, wherein the silicide layer is encapsulated by the metal fill after reacting a portion of the metal liner with a portion of the source/drain region.