Semiconductor device

A semiconductor device, comprising:

• a first electrode;
• a first semiconductor region provided on the first electrode and electrically connected to the first electrode, the first semiconductor region being of a first conductivity type;
• a second semiconductor region provided on the first semiconductor region, the second semiconductor region being of a second conductivity type;
• a third semiconductor region surrounding the second semiconductor region, the third semiconductor region being provided on the first semiconductor region, the third semiconductor region being of the first conductivity type, an impurity concentration of the first conductivity type in the third semiconductor region being higher than an impurity concentration of the first conductivity type in the first semiconductor region;
• a plurality of ring-shaped regions surrounding the second semiconductor region, the plurality of ring-shaped regions being separated from the second semiconductor region and the third semiconductor region, the plurality of ring-shaped regions being provided to be separated from each other, the plurality of ring-shaped regions being positioned between the second semiconductor region and the third semiconductor region, the plurality of ring-shaped regions being of the second conductivity type;
• a second electrode provided on the second semiconductor region and electrically connected to the second semiconductor region;
• a third electrode surrounding the second electrode, being provided to be separated from the second electrode on the third semiconductor region, the third electrode being electrically connected to the third semiconductor region;
• and
• a semi-insulating layer contacting the first semiconductor region, the second electrode, the plurality of ring-shaped regions, and the third electrode,
• the plurality of ring-shaped regions including
• a first ring-shaped region,
• a second ring-shaped region next to the first ring-shaped region,
• a third ring-shaped region provided between the second ring-shaped region and the third semiconductor region, and
• a fourth ring-shaped region next to the third ring-shaped region,
• a distance between the third ring-shaped region and the fourth ring-shaped region in a diametrical direction being longer than a distance between the first ring-shaped region and the second ring-shaped region in the diametrical direction, the diametrical direction being from the second semiconductor region toward the third semiconductor region.

A semiconductor device, comprising:

• a first electrode;
• a first semiconductor region provided on the first electrode and electrically connected to the first electrode, the first semiconductor region being of a first conductivity type;
• a second semiconductor region provided on the first semiconductor region, the second semiconductor region being of a second conductivity type;
• a third semiconductor region surrounding the second semiconductor region, the third semiconductor region being provided on the first semiconductor region, the third semiconductor region being of the first conductivity type, an impurity concentration of the first conductivity type in the third semiconductor region being higher than an impurity concentration of the first conductivity type in the first semiconductor region;
• a plurality of ring-shaped regions surrounding the second semiconductor region, the plurality of ring-shaped regions being separated from the second semiconductor region and the third semiconductor region, the plurality of ring-shaped regions being provided to be separated from each other, the plurality of ring-shaped regions being positioned between the second semiconductor region and the third semiconductor region, the plurality of ring-shaped regions being of the second conductivity type;
• a second electrode provided on the second semiconductor region and electrically connected to the second semiconductor region;
• a third electrode surrounding the second electrode, being provided to be separated from the second electrode on the third semiconductor region, the third electrode being electrically connected to the third semiconductor region;
• and
• a semi-insulating layer contacting the first semiconductor region, the second electrode, the plurality of ring-shaped regions, and the third electrode,
• the plurality of ring-shaped regions including a first ring-shaped region, and a second ring-shaped region provided between the first ring-shaped region and the third semiconductor region,
• an impurity concentration of the second conductivity type in the second ring-shaped region being lower than an impurity concentration of the second conductivity type in the first ring-shaped region.