SEMICONDUCTOR DEVICE AND METHOD OF MANUFACTURING THE SAME
First Claim
1. A semiconductor device comprising:
- a semiconductor layer of a first conductive type;
an element isolation insulation film formed on a front surface of said semiconductor layer;
a body layer of the first conductive type formed on the front surface of said semiconductor layer near one end of said element isolation insulation film;
a drain layer of a second conductive type formed on the front surface of said semiconductor layer near other end of said element isolation insulation film;
a source layer of the second conductive type formed on a front surface of said body layer;
a gate insulation film formed on said body layer;
a gate electrode extending from on said element isolation insulation film onto said body layer with said gate insulation film being interposed therebetween; and
a drift layer expanding in said semiconductor layer from under said drain layer to under said body layer under said source layer,wherein said drift layer is shallower immediately under said drain layer than under said element isolation insulation film, and gradually shallows from under said element isolation insulation film to the said body layer to be in contact with a bottom of said body layer.
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Accused Products
Abstract
A P type drift layer is formed in an N type epitaxial layer from under a drain layer to under an N type body layer under a source layer through under an element isolation insulation film. This P type drift layer is shallower immediately under the drain layer than under the element isolation insulation film, and gradually shallows from under the element isolation insulation film to the N type body layer to be in contact with the bottom of the N type body layer. Since the P type drift layer is thus diffused in a wide region, a wide current path is formed from the N type body layer to the drain layer, and the current drive ability is enhanced and the drain breakdown voltage is also increased.
79 Citations
9 Claims
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1. A semiconductor device comprising:
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a semiconductor layer of a first conductive type; an element isolation insulation film formed on a front surface of said semiconductor layer; a body layer of the first conductive type formed on the front surface of said semiconductor layer near one end of said element isolation insulation film; a drain layer of a second conductive type formed on the front surface of said semiconductor layer near other end of said element isolation insulation film; a source layer of the second conductive type formed on a front surface of said body layer; a gate insulation film formed on said body layer; a gate electrode extending from on said element isolation insulation film onto said body layer with said gate insulation film being interposed therebetween; and a drift layer expanding in said semiconductor layer from under said drain layer to under said body layer under said source layer, wherein said drift layer is shallower immediately under said drain layer than under said element isolation insulation film, and gradually shallows from under said element isolation insulation film to the said body layer to be in contact with a bottom of said body layer. - View Dependent Claims (2, 3, 4)
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5. A method of manufacturing a semiconductor device, comprising:
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implanting impurities of a second conductive type selectively in a front surface of a semiconductor layer of a first conductive type; forming an element isolation insulation film by selectively oxidizing a region where said impurities are implanted, and forming a drift layer of the second conductive type by diffusing said impurities, forming a body layer of the first conductive type near one end of said element isolation insulation film based on said element isolation insulation film; forming a gate insulation film on said body layer; forming a gate electrode from on said element isolation insulation film onto said body layer with said gate insulation film being interposed therebetween; and forming a source layer of the second conductive type on a front surface of said body layer and forming a drain layer of the second conductive type near other end of said element isolation insulation film, wherein said drift layer is diffused in said semiconductor layer from under said drain layer to under said body layer under said source layer so as to be shallower immediately under said drain layer than under said element isolation insulation film and gradually shallow from under said element isolation insulation film to said body layer. - View Dependent Claims (6, 7, 8, 9)
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Specification