Semiconductor device and method for manufacturing semiconductor device

A semiconductor device having a cell region that is an operation region and an edge termination region provided around the cell region in plan view, the semiconductor device comprising:

• a substrate;
• a drift region of a first conductivity type and a pillar region of a second conductivity type, the drift region extending in a thickness direction on the substrate, the pillar region extending in the thickness direction over the substrate, the drift region and the pillar region being alternately formed in an orthogonal direction with respect to the thickness direction across the cell region and the edge termination region;
• a plurality of breakdown voltage holding structures of the second conductivity type formed extending in the thickness direction from surfaces of the drift region and the pillar region in the edge termination region, the plurality of breakdown voltage holding structures being provided in a ring shape around the cell region and apart from each other;
• and
• a high-concentration region of the second conductivity type formed in surfaces of the breakdown voltage holding structures, the high-concentration region being higher in impurity concentration than the drift region,
• wherein no pillar region is formed under the high-concentration region in the thickness direction.

A method for manufacturing a semiconductor device having a cell region that is an operation region and an edge termination region provided around the cell region in plan view, the method comprising the steps of:

• (a) preparing a substrate;
• (b) forming a drift region of a first conductivity type and pillar regions of a second conductivity type, the drift region extending in a thickness direction on the substrate and the pillar regions extending in the thickness direction over the substrate, the drift region and the pillar regions being alternately formed in an orthogonal direction with respect to the thickness direction across the cell region and the edge termination region;
• (c) forming a RESURF layer of the second conductivity type across a plurality of the pillar regions in the edge termination region, the RESURF layer extending in the thickness direction from surfaces of the drift region and the plurality of pillar regions;
• and
• (d) forming a high-concentration region of the second conductivity type in a surface of the RESURF layer, the high-concentration region being higher in impurity concentration than the RESURF layer, no pillar region being formed under the high-concentration region in the thickness direction.