Semiconductor device and method of forming the same
First Claim
1. A semiconductor device comprising:
- a base body formed of semiconductor material, the base body having a trench formed from the top surface thereof;
a body region provided on the top surface side of the base body;
a source region provided on the top surface side of the body region;
a drain region provided on the bottom surface side of the base body;
a drift layer provided in the base body between the source region and the drain region;
a highly doped layer forming at least part of the drain region;
a gate insulator film formed of insulating material provided at least on sidewall surfaces of the trench; and
a gate electrode provided in the trench with the gate insulator film provided at least between the sidewall surfaces of the trench,wherein a product of a value of an insulation breakdown electric field strength and a value of a relative permittivity of the semiconductor material forming the base body is larger than a product of a normal value of an insulation breakdown electric field strength and a value of a relative permittivity of the insulating material forming the gate insulator film,wherein the trench penetrates the base body and the drift layer and reaches the highly doped layer on the drain region side,wherein a section of the trench deeper than the gate electrode is filled with an insulator having a normal value of an insulation breakdown electric field strength equal to or higher than the value of the insulation breakdown electric field strength of the semiconductor material of the base body,wherein the insulator at the bottom end of the gate electrode is thicker than the drift layer,wherein the sidewall surfaces of the trench located below the gate electrode is inclined to form a trapezoidal profile, andwherein the semiconductor material forming the base body is SiC, and each of the gate insulator film and the insulator filling the trench is SiO2.
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Accused Products
Abstract
A semiconductor device and a method of forming thereof has a base body has a field stopping layer, a drift layer, a current spreading layer, a body region, and a source contact region layered in the order on a substrate. A trench that reaches the field stopping layer or the substrate is provided. A gate electrode is provided in the upper half section in the trench. In a section deeper than the position of the gate electrode in the trench, an insulator is buried that has a normal value of insulation breakdown electric field strength equal to or greater than the value of the insulation breakdown electric field strength of the semiconductor material of the base body. This inhibits short circuit between a gate and a drain due to insulation breakdown of an insulator film at the bottom of the trench to realize a high breakdown voltage in a semiconductor device using a semiconductor material such as SiC. The sidewall surfaces of the trench located below the gate electrode is inclined to form a trapezoidal profile.
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Citations
19 Claims
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1. A semiconductor device comprising:
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a base body formed of semiconductor material, the base body having a trench formed from the top surface thereof; a body region provided on the top surface side of the base body; a source region provided on the top surface side of the body region; a drain region provided on the bottom surface side of the base body; a drift layer provided in the base body between the source region and the drain region; a highly doped layer forming at least part of the drain region; a gate insulator film formed of insulating material provided at least on sidewall surfaces of the trench; and a gate electrode provided in the trench with the gate insulator film provided at least between the sidewall surfaces of the trench, wherein a product of a value of an insulation breakdown electric field strength and a value of a relative permittivity of the semiconductor material forming the base body is larger than a product of a normal value of an insulation breakdown electric field strength and a value of a relative permittivity of the insulating material forming the gate insulator film, wherein the trench penetrates the base body and the drift layer and reaches the highly doped layer on the drain region side, wherein a section of the trench deeper than the gate electrode is filled with an insulator having a normal value of an insulation breakdown electric field strength equal to or higher than the value of the insulation breakdown electric field strength of the semiconductor material of the base body, wherein the insulator at the bottom end of the gate electrode is thicker than the drift layer, wherein the sidewall surfaces of the trench located below the gate electrode is inclined to form a trapezoidal profile, and wherein the semiconductor material forming the base body is SiC, and each of the gate insulator film and the insulator filling the trench is SiO2. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18)
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19. A method of forming a semiconductor device comprising the steps of:
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forming a base body formed of semiconductor material, the base body having a trench formed from the top surface thereof; forming a body region provided on the top surface side of the base body; forming a source region provided on the top surface side of the body region; forming a drain region provided on the bottom surface side of the base body; forming a drift layer provided in the base body between the source region and the drain region; forming a highly doped layer forming at least part of the drain region; forming a gate insulator film formed of insulating material provided at least on sidewall surfaces of the trench; and forming a gate electrode provided in the trench with the gate insulator film provided at least between the sidewall surface of the trench, wherein a product of a value of an insulation breakdown electric field strength and a value of a relative permittivity of the semiconductor material forming the base body is larger than a product of a normal value of an insulation breakdown electric field strength and a value of a relative permittivity of the insulating material forming the gate insulator film, wherein the trench penetrates the base body and the drift layer and reaches the highly doped layer on the drain region side, wherein a section of the trench deeper than the gate electrode is filled with an insulator having a normal value of an insulation breakdown electric field strength equal to or higher than the value of the insulation breakdown electric field strength of the semiconductor material of the base body, wherein the insulator at the bottom end of the gate electrode is thicker than the drift layer, wherein the sidewall surfaces of the trench located below the gate electrode is inclined to form a trapezoidal profile, and wherein the semiconductor material forming the base body is SiC, and each of the gate insulator film and the insulator filling the trench is SiO2.
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Specification