Self-aligned V-channel MOSFET
AssigneeTaiwan Semiconductor Manufacturing Company, Ltd.
InventorKa-Hing Fung
Life of this patent
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Abstract
Forming a high-κ/metal gate field effect transistor using a gate last process in which the channel region has a curved profile thus increasing the effective channel length improves the short channel effect. During the high-κ/metal gate process, after the sacrificial materials between the sidewall spacers are removed, the exposed semiconductor substrate surface at the bottom of the gate trench cavity is etched to form a curved recess. Subsequent deposition of high-κ gate dielectric layer and gate electrode metal into the gate trench cavity completes the high-κ/metal gate field effect transistor having a curved channel region that has a longer effective channel length.
Claims18
A metal oxide semiconductor field effect transistor device comprising:
- a semiconductor substrate;
- a source region and a drain region formed in the semiconductor substrate;
- a recessed channel region in the semiconductor substrate between the source region and the drain region, the recessed channel region formed by a pair of inclined surfaces in the semiconductor substrate wherein the inclined surfaces are oriented substantially along <111> crystal directions;
- a high-κ gate dielectric layer overlying the recessed channel region;
- a metal gate electrode overlying the gate dielectric layer;
- and
- a pair of spacers disposed on two sides of the gate electrode, wherein the high-κ gate dielectric layer conformally lines the interface between the spacers and the gate electrode.
A metal oxide semiconductor field effect transistor device comprising:
- a semiconductor substrate;
- a source region and a drain region formed in the semiconductor substrate;
- a pair of spacers formed over the semiconductor substrate and defining a gate trench therebetween, the spacers forming sidewalls of the gate trench;
- a recessed channel region formed at the bottom of the gate trench between the source region and the drain region, the recessed channel region formed by a pair of inclined surfaces oriented substantially along <111> crystal directions;
- a high-κ gate dielectric layer conformally lining the sidewalls of the gate trench and overlying the recessed channel region;
- and
- a metal gate electrode overlying the gate dielectric layer.
A metal oxide semiconductor field effect transistor device comprising:
- a semiconductor substrate;
- a source region and a drain region formed in the semiconductor substrate;
- a recessed channel region formed by a pair of inclined surfaces oriented substantially along <111> crystal directions;
- a high-κ gate dielectric layer overlying the recessed channel region;
- a metal gate electrode overlying the gate dielectric layer;
- and
- a pair of spacers disposed on two sides of the gate electrode, wherein the high-κ gate dielectric layer conformally lines the interface between the spacers and the gate electrode.
Dependencies are inferred from the claim text.