Techniques providing metal gate devices with multiple barrier layers

摘要

A semiconductor device with a metal gate is disclosed. An exemplary semiconductor device with a metal gate includes a semiconductor substrate, source and drain features on the semiconductor substrate, a gate stack over the semiconductor substrate and disposed between the source and drain features. The gate stack includes a HK dielectric layer formed over the semiconductor substrate, a plurality of barrier layers of a metal compound formed on top of the HK dielectric layer, wherein each of the barrier layers has a different chemical composition; and a stack of metals gate layers deposited over the plurality of barrier layers.

主权项

1. 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; anda 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; anda second stack of metal gate layers disposed over the plasma-deposited titanium nitride barrier layer.