Method to improve reliability of replacement gate device

摘要

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; performing a first rapid thermal anneal; removing the sacrificial layer; and depositing a metal layer of low resistivity metal for gap fill.

主权项

1. 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 the sacrificial layer from the thin metal layer to expose an entirety of the thin metal layer directly over a channel region of the semiconductor device; anddepositing a metal layer of low resistivity metal directly on an entirety of the thin metal layer in the gate stack.