SEMICONDUCTOR DEVICE AND METHOD FOR MANUFACTURING SAME
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Abstract
A semiconductor device and a method of manufacturing the same, to appropriately determine an impurity concentration distribution of a field relieving region and reduce an ON-resistance. The semiconductor device includes a substrate, a first drift layer, a second drift layer, a first well region, a second well region, a current control region, and a field relieving region. The first well region is disposed continuously from an end portion adjacent to the vicinity of outer peripheral portion of the second drift layer to a portion of the first drift layer below the vicinity of outer peripheral portion. The field relieving region is so disposed in the first drift layer as to be adjacent to the first well region.
34 Citations
23 Claims
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1-11. -11. (canceled)
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12. A semiconductor device comprising:
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a substrate formed of silicon carbide including a first conductivity type impurity; a first drift layer formed of silicon carbide including a first conductivity type impurity of first concentration, being disposed entirely on a surface of said substrate; a second drift layer formed of silicon carbide including a first conductivity type impurity of second concentration higher than said first concentration, being disposed on a surface of said first drift layer; a plurality of well regions containing a second conductivity type impurity, being disposed in said second drift layer; a current control region disposed in second drift layer between a pair of said well regions; a gate electrode disposed above said current control region; and a gate insulating film disposed between said gate electrode and said current control region, wherein the concentration of the first conductivity type impurity of said second drift layer varies in accordance with the depth from its surface. - View Dependent Claims (13, 14, 15, 16, 17, 18, 19, 20)
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21. A method of manufacturing a semiconductor device, comprising:
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preparing a substrate formed of silicon carbide including a first conductivity type impurity; forming a first drift layer made of silicon carbide including a first conductivity type impurity of first concentration entirely on a surface of said substrate by epitaxial growth; forming a second drift layer made of silicon carbide including a first conductivity type impurity of second concentration higher than said first concentration entirely on a surface of said first drift layer by epitaxial growth; removing the vicinity of outer peripheral portion of said second drift layer with a step portion at an end portion being tapered; a current control region providing forming a first well region at an end portion adjacent to said vicinity of outer peripheral portion of said second drift layer and in a portion of said first drift layer below said vicinity of outer peripheral portion and forming a second well region in said second drift layer except the end portion adjacent to said vicinity of outer peripheral portion by selectively implanting a second conductivity type impurity, to thereby determine said second drift layer between said first and second well regions as a current control region; and forming a field relieving region in said first drift layer as to be adjacent to said first well region. - View Dependent Claims (22, 23)
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Specification