Method to improve reliability of replacement gate device
AssigneeInternational Business Machines Corporation
InventorsTakashi Ando, Eduard A. Cartier, Kisik Choi, Vijay Narayanan
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Abstract
A method of fabricating a replacement gate stack for a semiconductor device includes the following steps after removal of a dummy gate: growing a high-k dielectric layer over the area vacated by the dummy gate; depositing a thin metal layer over the high-k dielectric layer; depositing a sacrificial layer over the thin metal layer; annealing the structure at a high temperature of not less than 800° C.; removing the sacrificial layer; and depositing a metal layer of low resistivity metal for gap fill. Optionally, a second annealing step can be performed after the first anneal. This second anneal is performed as a millisecond anneal using a flash lamp or a laser.
Claims5
A method of fabricating a gate stack for a semiconductor device, said method comprising steps of:
- after removal of a dummy gate, providing a replacement gate structure by performing steps of:
- growing a high-k dielectric layer over an area vacated by the dummy gate;
- depositing a thin metal layer over the high-k dielectric layer;
- depositing a sacrificial layer over the thin metal layer;
- performing a first rapid thermal anneal of the replacement gate structure at a high temperature of not less than 800° C.;
- removing both the thin metal layer and the sacrificial layer;
- performing a second rapid thermal anneal at a temperature range between 400° C. and 800° C., inclusive;
- re-depositing a thin metal layer over the high-k dielectric layer after performing the second rapid thermal anneal;
- and
- depositing a second metal layer.
Dependencies are inferred from the claim text.