Semiconductor device

A semiconductor device, comprising:

• a first electrode;
• a first semiconductor region provided on the first electrode, the first semiconductor region being of a first conductivity type and being electrically connected to the first electrode;
• a second semiconductor region provided on a portion of the first semiconductor region, the second semiconductor region being of the first conductivity type, an impurity concentration of the first conductivity type in the second semiconductor region being lower than an impurity concentration of the first conductivity type in the first semiconductor region;
• a third semiconductor region provided on another portion of the first semiconductor region, the third semiconductor region being of a second conductivity type and being arranged with at least a portion of the second semiconductor region in a first direction perpendicular to a second direction, the second direction being from the first electrode toward the first semiconductor region;
• a fourth semiconductor region provided in at least a portion between the first semiconductor region and the third semiconductor region, the fourth semiconductor region being of the first conductivity type, an impurity concentration of the first conductivity type in the fourth semiconductor region being lower than the impurity concentration of the first conductivity type in the first semiconductor region and higher than the impurity concentration of the first conductivity type in the second semiconductor region;
• a fifth semiconductor region provided between the first semiconductor region and the fourth semiconductor region, the fifth semiconductor region being of the first conductivity type, an impurity concentration of the first conductivity type in the fifth semiconductor region being lower than the impurity concentration of the first conductivity type in the fourth semiconductor region;
• a sixth semiconductor region provided on the third semiconductor region, the sixth semiconductor region being of the second conductivity type, an impurity concentration of the second conductivity type in the sixth semiconductor region being higher than an impurity concentration of the second conductivity type in the third semiconductor region;
• a seventh semiconductor region provided selectively on the sixth semiconductor region, the seventh semiconductor region being of the first conductivity type;
• a gate electrode opposing the second semiconductor region, the sixth semiconductor region, and the seventh semiconductor region with a gate insulating layer interposed;
• and
• a second electrode provided on the sixth semiconductor region and the seventh semiconductor region and electrically connected to the sixth semiconductor region and the seventh semiconductor region.