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 the first semiconductor region, the second semiconductor region being of a second conductivity type;
• a third semiconductor region provided around the second semiconductor region along a first plane crossing a first direction, the third semiconductor region being of the second conductivity type and being separated from the second semiconductor region, the first direction being from the first electrode toward the first semiconductor region;
• a fourth semiconductor region provided around the third semiconductor region along the first plane, the fourth semiconductor region being of the first conductivity type, an impurity concentration of the first conductivity type in the fourth semiconductor region being greater than an impurity concentration of the first conductivity type in the first semiconductor region;
• a second electrode provided on the second semiconductor region and electrically connected to the second semiconductor region;
• and
• a third electrode provided on the third and fourth semiconductor regions, electrically connected to the third and fourth semiconductor regions, and separated from the second electrode.