Semiconductor device and method for manufacturing

A semiconductor device, comprising:

• a first electrode;
• a second electrode positioned above the first electrode;
• a semiconductor layer positioned between the first electrode and the second electrode in a vertical direction, the semiconductor layer including
• an element region,
• a termination region surrounding the element region,
• a first semiconductor region located in the element region and the termination region, the first semiconductor region being of a first conductivity type,
• a plurality of guard ring regions located in the termination region at an upper surface of the semiconductor layer, the plurality of guard ring regions surrounding the element region, the plurality of guard ring regions being of a second conductivity type, and
• a high-concentration region located between two mutually-adjacent guard ring regions among the plurality of guard ring regions, the high-concentration region being of the first conductivity type, the two mutually-adjacent guard ring regions including an outer guard ring region and an inner guard ring region, the inner guard ring region being positioned between the outer guard ring region and the element region, the high-concentration region being separated from the inner guard ring region and the outer guard ring region, a first-conductivity-type impurity concentration in the high-concentration region being greater than a first-conductivity-type impurity concentration in the first semiconductor region.

A method for manufacturing a semiconductor device, the method comprising:

• preparing a semiconductor layer including
• an element region,
• a termination region surrounding the element region,
• a first semiconductor region located in the element region and the termination region, the first semiconductor region being of a first conductivity type, and
• a plurality of guard ring regions located on the first semiconductor region in the termination region, the plurality of guard ring regions surrounding the element region, the plurality of guard ring regions being of a second conductivity type;
• forming a plurality of conductive parts so that portions of the plurality of conductive parts are positioned respectively above the plurality of guard ring regions, and so that the plurality of conductive parts are electrically connected respectively with the plurality of guard ring regions;
• and
• forming a high-concentration region on the first semiconductor region between two mutually-adjacent guard ring regions among the plurality of guard ring regions by performing ion implantation using the plurality of conductive parts as a mask, the high-concentration region being of the first conductivity type, a first-conductivity-type impurity concentration in the high-concentration region being greater than a first-conductivity-type impurity concentration in the first semiconductor region, a first-conductivity-type impurity dose in the ion implantation being not more than 3.5×1012/cm2.