FinFET gate structure and method for fabricating the same

摘要

A semiconductor device includes a n-type gate structure over a first semiconductor fin, in which the n-type gate structure includes a n-type work function metal layer overlying the first high-k dielectric layer. The n-type work function metal layer includes a TiAl (titanium aluminum) alloy, in which an atom ratio of Ti (titanium) to Al (aluminum) is in a range substantially from 1 to 3. The semiconductor device further includes a p-type gate structure over a second semiconductor fin, in which the p-type gate structure includes a p-type work function metal layer overlying the second high-k dielectric layer. The p-type work function metal layer includes titanium nitride (TiN), in which an atom ratio of Ti to N (nitrogen) is in a range substantially from 1:0.9 to 1:1.1.

主权项

1. A semiconductor device, comprising:
a semiconductor substrate; a first semiconductor fin on the semiconductor substrate; and a n-type gate structure over the first semiconductor fin, the n-type gate structure comprising:
a first initial layer over the first semiconductor fin;a first high-k dielectric layer over the first initial layer and enclosed by a first gate spacer;a n-type work function metal layer overlying the first high-k dielectric layer, the n-type work function metal layer comprising a TiAl (titanium aluminum) alloy, wherein an atom ratio of Ti (titanium) to Al (aluminum) is in a range substantially from 1 to 3, wherein both surfaces of the n-type work function metal layer contain an oxygen concentration substantially less than 10 atom percent (at %);a first blocking metal layer overlying the n-type work function metal layer; anda first metal filler peripherally enclosed by the first blocking metal layer.