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.

Abstract: The present invention provides a MOSFET and so forth that offer high breakdown voltage and low on-state loss (high channel mobility and low gate threshold voltage) and that can easily achieve normally OFF. A drift layer 2 of a MOSFET made of silicon carbide according to the present invention has a first region 2a and a second region 2b. The first region 2a is a region from the surface to a first given depth. The second region 2b is formed in a region deeper than the first given depth. The impurity concentration of the first region 2a is lower than the impurity concentration of the second region 2b.

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.

Abstract: The present invention provides a MOSFET and so forth that offer high breakdown voltage and low on-state loss (high channel mobility and low gate threshold voltage) and that can easily achieve normally OFF. A drift layer 2 of a MOSFET made of silicon carbide according to the present invention has a first region 2a and a second region 2b. The first region 2a is a region from the surface to a first given depth. The second region 2b is formed in a region deeper than the first given depth. The impurity concentration of the first region 2a is lower than the impurity concentration of the second region 2b.