FinFETs and methods for forming the same
AssigneeTaiwan Semiconductor Manufacturing Company, Ltd.
InventorJeffrey Junhao Xu
Life of this patent
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Abstract
A FinFET includes a semiconductor fin including an inner region, and a germanium-doped layer on a top surface and sidewall surfaces of the inner region. The germanium-doped layer has a higher germanium concentration than the inner region. The FinFET further includes a gate dielectric over the germanium-doped layer, a gate electrode over the gate dielectric, a source region connected to a first end of the semiconductor fin, and a drain region connected to a second end of the semiconductor fin opposite the first end. Through the doping of germanium in the semiconductor fin, the threshold voltage may be tuned.
Claims20
A device comprising:
- a semiconductor fin comprising:
- an inner region;
- and
- a germanium-doped layer on a top surface and sidewall surfaces of the inner region, wherein the germanium-doped layer has a higher germanium concentration than the inner region;
- a gate stack comprising:
- a gate dielectric over the germanium-doped layer;
- and
- a gate electrode over the gate dielectric;
- a source region connected to a first end of the semiconductor fin;
- a drain region connected to a second end of the semiconductor fin opposite the first end, wherein the germanium-doped layer comprises an end facing the source region, and the end is substantially vertically aligned to a sidewall of the gate stack;
- and
- a shallow trench isolation region having opposite portions on opposite sides of the semiconductor fin, wherein the germanium-doped layer comprises:
- a sidewall portion having an inner sidewall surface contacting one of the sidewall surfaces of the inner region;
- and
- an outer sidewall surface vertically aligned to a sidewall of the shallow trench isolation region.
A device comprising:
- a semiconductor substrate;
- an isolation region extending into the semiconductor substrate;
- a semiconductor strip between opposite portions of the isolation region, wherein opposite edges of the semiconductor strip are in physical contact with edges of the opposite portions of the isolation region;
- and
- a Fin Field-Effect Transistor (FinFET) comprising:
- a semiconductor fin comprising:
- a silicon inner region substantially free from germanium;
- and
- a germanium-doped layer comprising:
- a top portion overlapping the silicon inner region;
- and
- a sidewall portion on a sidewall of the silicon inner region, wherein a bottom end of the sidewall portion is substantially at a same level as a top surface of the isolation region, and the germanium-doped layer has an outer edge vertically aligned to an interface between the semiconductor strip and the isolation region;
- a gate dielectric contacting the germanium-doped layer;
- and
- a gate electrode over the gate dielectric.
A device comprising:
- a semiconductor substrate;
- an isolation region extending into the semiconductor substrate, wherein a portion of the semiconductor substrate is located between opposite portions of the isolation region to form a semiconductor strip, and the opposite portions of the isolation region have a first horizontal distance;
- and
- a Fin Field-Effect Transistor (FinFET), wherein the FinFET is an n-type FinFET comprising:
- a semiconductor fin comprising:
- a silicon fin higher than the isolation region and overlapping the semiconductor strip;
- and
- a germanium-doped layer comprising a first sidewall portion and a second sidewall portion contacting opposite sidewalls of the silicon fin to form a first vertical interface and a second vertical interface, respectively, and a second horizontal distance between the first vertical interface and the second vertical interface is smaller than the first horizontal distance, wherein the germanium-doped layer has a higher germanium concentration than the silicon fin;
- a gate dielectric comprising portions on sidewalls of the germanium-doped layer;
- and
- a gate electrode over the gate dielectric.
Dependencies are inferred from the claim text.