FinFET gate structure and method for fabricating the same
First Claim
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; and
a first metal filler peripherally enclosed by the first blocking metal layer.
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Abstract
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.
26 Citations
19 Claims
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1. A semiconductor device, comprising:
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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; and a first metal filler peripherally enclosed by the first blocking metal layer. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10)
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11. A semiconductor device, comprising:
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a semiconductor substrate; a first semiconductor fin and a second semiconductor fin on the semiconductor substrate, wherein the first semiconductor fin and the second semiconductor fin are separated by an isolation structure; and a n-type gate structure comprising a first initial layer over the first semiconductor fin and enclosed by a first gate spacer, and a p-type gate structure comprising a second initial layer over the second semiconductor fin and enclosed by a second gate spacer, each of the n-type gate structure and the p-type gate structure comprising; a high-k dielectric layer over the first initial layer and the second initial layer; a first TiN layer overlying the high-k dielectric layer; a TaN layer overlying the first TiN layer; a second TiN layer overlying the TaN layer; a TiAl layer overlying the second TiN layer; a third TiN layer overlying the TiAl layer; and a metal filler peripherally enclosed by the third TiN layer; wherein the TiAl layer enclosed by the first gate spacer is a n-type work function metal layer, wherein an atom ratio of Ti (titanium) to Al (aluminum) is in a range substantially from 1 to 3; and the second TiN layer enclosed by the second gate spacer is a p-type work function metal layer, wherein an atom ratio of Ti to N (nitrogen) is in a range substantially from 1;
0.9 to 1;
1.1. - View Dependent Claims (12, 13, 14)
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15. A method for forming a semiconductor device, the method comprising:
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forming a first semiconductor fin and a second semiconductor fin on a semiconductor substrate, wherein the first semiconductor fin and the second semiconductor fin are separated by an isolation structure; forming a first initial layer enclosed by a first gate spacer over the first semiconductor fin, and a second initial layer enclosed by a second gate spacer over the second semiconductor fin; forming a high-k dielectric layer over the first initial layer and the second initial layer; forming a first TiN layer over the high-k dielectric layer; forming a TaN layer over the first TiN layer; forming a second TiN layer over the TaN layer; forming a TiAl layer over the second TiN layer; forming a third TiN layer over the TiAl layer; and forming a metal filler peripherally enclosed by the third TiN layer; wherein the TiAl layer enclosed by the first gate spacer acts as a n-type work function metal layer, wherein an atom ratio of Ti (titanium) to Al (aluminum) is in a range substantially from 1 to 3; and the second TiN layer enclosed by the second gate spacer acts as a p-type work function metal layer, wherein an atom ratio of Ti to N (nitrogen) is in a range substantially from 1;
0.9 to 1;
1.1. - View Dependent Claims (16, 17, 18, 19)
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Specification