Non-planar III-V field effect transistors with conformal metal gate electrode and nitrogen doping of gate dielectric interface
A high-k gate dielectric interface with a group III-V semiconductor surface of a non-planar transistor channel region is non-directionally doped with nitrogen. In nanowire embodiments, a non-directional nitrogen doping of a high-k gate dielectric interface is performed before or concurrently with a conformal gate electrode deposition through exposure of the gate dielectric to liquid, vapor, gaseous, plasma, or solid state sources of nitrogen. In embodiments, a gate electrode metal is conformally deposited over the gate dielectric and an anneal is performed to uniformly accumulate nitrogen within the gate dielectric along the non-planar III-V semiconductor interface.
1. A non-planar field effect transistor (FET), comprising:
a source region and a drain region with a III-V semiconductor channel region disposed there between;
a gate dielectric layer disposed over the semiconductor channel region, wherein the gate dielectric layer comprises a metal oxide, and further comprises nitrogen dopants incorporated in the gate dielectric layer, the nitrogen dopants are proximal an interface between the gate dielectric and the III-V semiconductor channel region; and
a gate electrode disposed over the gate dielectric layer.
2. The FET of claim 1 , wherein the III-V semiconductor channel region is in direct contact with the gate dielectric, wherein the gate dielectric layer comprises a nitrogen-rich region proximal the interface with the III-V semiconductor channel region, the nitrogen-rich region having more nitrogen relative to a region of the gate dielectric distal from the interface.
3. The FET of claim 2 , wherein the semiconductor channel region comprises a wire passing through the gate dielectric layer with the gate dielectric completely wrapping around the channel region and wherein the nitrogen-rich region of the gate dielectric layer also wraps completely around the channel.
4. The FET of claim 1 , further comprising a metal nitride layer disposed between the gate electrode and the gate dielectric, the metal nitride interfacing the gate dielectric.
5. The FET of claim 4 , wherein the metal nitride comprises at least one of: Ti, V, Mo, Ta, or W.
6. The FET of claim 4 , wherein the gate electrode comprises a work function metal disposed over the metal nitride, the work function metal having a composition that sets the work function of the gate electrode in the presence of the metal nitride.
7. The FET of claim 6 , wherein the work function metal comprises at least one of: Ru, Co, Ir, Ni, Pd, or Pt.
8. The FET of claim 1 , wherein the metal oxide is an oxide of a metal selected from the group consisting of Al, Zr, Hf, Ta and La.
9. The FET of claim 8 , wherein the metal oxide is a metal silicate further comprising silicon.
10. A non-planar group III-V field effect transistor (FET), comprising:
a source region and a drain region with a III-V semiconductor nanowire extending there between;
a gate dielectric layer wrapping completely around a length of the III-V semiconductor wire between the source and drain regions, wherein the gate dielectric layer comprises a metal oxide, and further comprises a nitrogen-rich region formed of nitrogen dopants incorporated in the gate dielectric layer, the nitrogen-rich region is proximal an interface between the gate dielectric layer and the semiconductor channel region, the nitrogen-rich region also wrapping around at least a portion of the III-V semiconductor wire; and
a metal gate electrode wrapping completely around the gate dielectric layer.
11. The non-planar group III-V field effect transistor (FET) of claim 10 , wherein the gate metal comprises a lower concentration of nitrogen than does the nitrogen-rich region of the gate dielectric layer.
12. The non-planar group III-V field effect transistor (FET) of claim 11 , further comprising a metal nitride layer disposed between the gate electrode and the gate dielectric, the metal nitride interfacing the gate dielectric.
13. A mobile computing platform comprising:
an integrated circuit comprising the FET of claim 10 ,
a display screen; and
a wireless transceiver.