Semiconductor device and method of manufacturing semiconductor device
First Claim
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1. A semiconductor device, comprising:
- a semiconductor layer of a first conductivity type made of SiC having a first Si surface;
a gate trench dug down from the first Si surface of the semiconductor layer such that the gate trench has a bottom surface parallel to the first Si surface and a side surface orthogonal to the first Si surface, the bottom surface being a second Si surface;
a body region of a second conductivity type formed in the semiconductor layer and defining one part of the side surface of the gate trench;
a source region of the first conductivity type formed on a surface layer portion of the body region and defining another part of the side surface of the gate trench;
a drain region of the first conductivity type formed on an opposite side of the source region from the body region and defining the bottom surface of the gate trench;
a gate insulating film including an insulating film bottom portion formed on the bottom surface of the gate trench and an insulating film side portion formed on the side surface of the gate trench, the insulating film bottom portion and the insulating film side portion intersecting each other and having respective uniform thicknesses; and
a gate electrode embedded in the gate trench through the gate insulating film, whereinthe ratio of the thickness of the insulating film bottom portion to the thickness of the insulating film side portion is between 0.3 and 1.0.
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Abstract
The semiconductor device according to the present invention includes: a semiconductor layer of a first conductivity type made of SiC having an Si surface; a gate trench dug down from the surface of the semiconductor layer; a gate insulating film formed on a bottom surface and a side surface of the gate trench so that the ratio of the thickness of a portion located on the bottom surface to the thickness of a portion located on the side surface is 0.3 to 1.0; and a gate electrode embedded in the gate trench through the gate insulating film.
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Citations
15 Claims
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1. A semiconductor device, comprising:
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a semiconductor layer of a first conductivity type made of SiC having a first Si surface; a gate trench dug down from the first Si surface of the semiconductor layer such that the gate trench has a bottom surface parallel to the first Si surface and a side surface orthogonal to the first Si surface, the bottom surface being a second Si surface; a body region of a second conductivity type formed in the semiconductor layer and defining one part of the side surface of the gate trench; a source region of the first conductivity type formed on a surface layer portion of the body region and defining another part of the side surface of the gate trench; a drain region of the first conductivity type formed on an opposite side of the source region from the body region and defining the bottom surface of the gate trench; a gate insulating film including an insulating film bottom portion formed on the bottom surface of the gate trench and an insulating film side portion formed on the side surface of the gate trench, the insulating film bottom portion and the insulating film side portion intersecting each other and having respective uniform thicknesses; and a gate electrode embedded in the gate trench through the gate insulating film, wherein the ratio of the thickness of the insulating film bottom portion to the thickness of the insulating film side portion is between 0.3 and 1.0. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11)
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12. A method of manufacturing a semiconductor device, comprising the steps of:
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forming a gate trench on a surface layer portion of a semiconductor layer of a first conductivity type made of SiC having a first Si surface, the gate trench being dug down from the first Si surface of the semiconductor layer such that the gate trench has a bottom surface parallel to the first Si surface and a side surface orthogonal to the first Si surface, the bottom surface being a second Si surface; forming a body region of a second conductivity type in the semiconductor layer to define one part of the side surface of the gate trench; forming a source region of a first conductivity type on a surface layer portion of the body region to define another part of the side surface of the gate trench; forming a drain region of a first conductivity type on an opposite side of the source region from the body region to define the bottom surface of the gate trench; forming a gate insulating film including an insulating film bottom portion to be formed on the bottom surface and an insulating film side portion to be formed the side surface of the gate trench by oxidizing the bottom surface and the side surface of the gate trench in gas containing nitrogen and oxygen at a heat treatment temperature of not less than 1200°
C., the insulating film bottom portion and the insulating film side portion intersecting each other and having respective uniform thicknesses; andforming a gate electrode on the gate insulating film to fill up the gate trench. - View Dependent Claims (13, 14, 15)
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Specification