Semiconductor device and method of manufacturing the same
AssigneeRenesas Electronics Corporation
InventorsTakuho Kamada, Koji Ogata, Kiyoyuki Satou
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Abstract
A semiconductor device includes an n-type semiconductor substrate, a trench, and a gate electrode formed in the trench via a gate insulating film. An absolute value of a difference between a thickness of the gate insulating film formed on a corner portion of the trench and a thickness of the gate insulating film formed on the bottom portion of the trench is smaller than an absolute value of a difference between the thickness of the gate insulating film formed on the corner portion of the trench and a thickness of the gate insulating film formed on the sidewall portion of the trench.
Claims15
A semiconductor device comprising:
- a semiconductor substrate of a first conductivity type having an upper surface and a lower surface;
- a first trench formed in the semiconductor substrate on an upper surface side of the semiconductor substrate;
- a first insulating film formed in the first trench;
- and
- a conductive film buried in the first trench via the first insulating film,
- wherein a surface of the first trench has:
- a first sidewall portion formed from the upper surface of the semiconductor substrate toward an inside of the semiconductor substrate to a predetermined depth;
- a first bottom portion located inside the semiconductor substrate;
- and
- a first corner portion connecting the first sidewall portion and the first bottom portion,
- wherein an absolute value ΔTB of a difference between a thickness of the first insulating film formed on the first corner portion and a thickness of the first insulating film formed on the first bottom portion is smaller than an absolute value ΔTA of a difference between the thickness of the first insulating film formed on the first corner portion and a thickness of the first insulating film formed on the first sidewall portion, and
- wherein a crystal plane of the semiconductor substrate at each of the first sidewall portions, the first bottom portion, and the first corner portions is a (100) plane.
A method of manufacturing a semiconductor device, the method comprising:
- (a) preparing a semiconductor substrate of a first conductivity type having an upper surface and a lower surface;
- (b) forming a first trench in the semiconductor substrate on an upper surface side of the semiconductor substrate;
- (c) forming a first insulating film in the first trench;
- and
- (d) forming a conductive film so as to fill the first trench via the first insulating film,
- wherein a surface of the first trench has:
- a first sidewall portion formed from the upper surface of the semiconductor substrate toward an inside of the semiconductor substrate to a predetermined depth;
- a first bottom portion located inside the semiconductor substrate;
- and
- a first corner portion connecting the first sidewall portion and the first bottom portion,
- wherein an absolute value ΔTB of a difference between a thickness of the first insulating film formed on the first corner portion and a thickness of the first insulating film formed on the first bottom portion is smaller than an absolute value ΔTA of a difference between the thickness of the first insulating film formed on the first corner portion and a thickness of the first insulating film formed on the first sidewall portion, and
- wherein a crystal plane of the semiconductor substrate at each of the first sidewall portions, the first bottom portion, and the first corner portions is a (100) plane.
Dependencies are inferred from the claim text.