Structure and method to form a thermally stable silicide in narrow dimension gate stacks

摘要

An integrated circuit is provided including a narrow gate stack having a width less than or equal to 65 nm, including a silicide region comprising Pt segregated in a region of the silicide away from the top surface of the silicide and towards an lower portion defined by a pulldown height of spacers on the sidewalls of the gate conductor. In a preferred embodiment, the spacers are pulled down prior to formation of the silicide. The silicide is first formed by a formation anneal, at a temperature in the range 250° C. to 450° C. Subsequently, a segregation anneal at a temperature in the range 450° C. to 550° C. The distribution of the Pt along the vertical length of the silicide layer has a peak Pt concentration within the segregated region, and the segregated Pt region has a width at half the peak Pt concentration that is less than 50% of the distance between the top surface of the silicide layer and the pulldown spacer height.