Patent ID: 8847333

Claim:
A semiconductor device with a metal gate comprising: a first transistor of a first type of conductivity, the first transistor including: a relatively-nitrogen-free high-k (HK) dielectric layer disposed over a semiconductor substrate; an atomic layer deposition (ALD)-deposited titanium nitride barrier layer formed on top of the HK dielectric layer such that the ALD-deposited titanium nitride barrier layer physically contacts the HK dielectric layer; a plasma-deposited titanium nitride barrier layer formed on top of the ALD-deposited titanium nitride barrier layer such that the plasma-deposited titanium nitride barrier layer physically contacts the ALD-deposited titanium nitride barrier layer; and a first stack of metal gate layers disposed over the plasma-deposited titanium nitride barrier layer; and a second transistor of a second type of conductivity that is opposite the first type of conductivity, the second transistor including: the relatively-nitrogen-free high-k (HK) dielectric layer disposed over the semiconductor substrate; the ALD-deposited titanium nitride barrier layer formed on top of the HK dielectric layer such that the ALD-deposited titanium nitride barrier layer physically contacts the HK dielectric layer; the plasma-deposited titanium nitride barrier layer formed on top of the ALD-deposited titanium nitride barrier layer such that the plasma-deposited titanium nitride barrier layer physically contacts the ALD-deposited titanium nitride barrier layer; and a second stack of metal gate layers disposed over the plasma-deposited titanium nitride barrier layer.