Silicide contacts having different shapes on regions of a semiconductor device
A structure and method for fabricating silicide contacts for semiconductor devices is provided. Specifically, the structure and method involves utilizing chemical vapor deposition (CVD) and annealing to form silicide contacts of different shapes, selectively on regions of a semiconductor field effect transistor (FET), such as on source and drain regions. The shape of silicide contacts is a critical factor that can be manipulated to reduce contact resistance. Thus, the structure and method provide silicide contacts of different shapes with low contact resistance, wherein the silicide contacts also mitigate leakage current to enhance the utility and performance of FETs in low power applications.
1. A semiconductor device comprising:
a substrate;
a source region and a drain region of the semiconductor device grown on the substrate;
a gate disposed on the substrate between the source region and the drain region;
an interlayer dielectric disposed on the source region and the drain region, and disposed on and adjacent to the gate;
openings inside the interlayer dielectric to the source region, and to the drain region;
one or more shaped surface areas on the source region and the drain region, wherein the one or more shaped surface areas are hexagonal-like surface areas, pentagonal-like surface areas, or brimmed surface areas;
a contact layer disposed on and adjacent to the interlayer dielectric, and the one or more shaped surface areas, wherein the contact layer provides a contact conformal to the one or more shaped surface areas, and wherein the contact layer is a silicide that comprises nickel silicide, cobalt di-silicide, or erbium di-silicide;
a metal layer disposed on and adjacent to the contact layer;
a planarized surface, wherein a portion of the contact layer and a portion of the metal layer are removed selective to the interlayer dielectric; and
a capping layer disposed on the planarized surface.
2. The semiconductor device of claim 1 , wherein the semiconductor device is a field effect transistor comprising the source region and the drain region.
3. The semiconductor device of claim 1 , wherein:
the substrate comprises bulk silicon or a semiconductor-on-insulator, and wherein a portion of the substrate is doped with p-type or n-type dopants; and
the substrate comprises germanium (Ge), silicon-carbon (SiC), other group IV materials, gallium arsenide (GaAs), aluminum gallium arsenide (AlGaAs), indium arsenide (InAs), or other group III/V materials.
4. The semiconductor device of claim 3 , further comprising source-drain extensions formed in a portion of the substrate.
5. The semiconductor device of claim 4 , wherein the gate further comprises:
a gate dielectric layer and a dielectric spacer; and
a metal layer, poly-silicon layer, or metal and poly-silicon layer disposed on the gate dielectric layer.
6. The semiconductor device of claim 5 , wherein:
the dielectric spacer includes nitride, oxide, any other dielectric material, or a combination thereof; and
the interlayer dielectric includes nitride, oxide, any other dielectric material, or a combination thereof.
7. The semiconductor device of claim 1 , wherein:
the openings are formed utilizing an etching/removal technique that includes anisotropic RIE, isotropic RIE, wet etching, plasma etching, or ion milling to etch the interlayer dielectric.
8. The semiconductor device of claim 1 , wherein:
the source region further comprises a raised source region;
the drain region further comprises a raised drain region;
the raised source region and the raised drain region are at a distance from a transistor channel region;
the distance from the transistor channel regions is adjustable such that leakage current is mitigated; and
the source region and the drain region comprise epitaxial material, in-situ doped epitaxial material, ion implanted and annealed semiconductor material, or a combination thereof.
9. The semiconductor device of claim 8 , wherein:
the one or more shaped surface areas are on the raised source region and the raised drain region.