| 摘要 |
PROBLEM TO BE SOLVED: To reduce an on-state resistance by a method wherein a dopant is vertically distributed in a thickness direction of a layer in an injection region and the injection region is approximately equalized. SOLUTION: A blocking layer provides each P section 30 and N section 32 alternatively. Each vertical type section 30 and 32 has dopant concentration from approximately 1E<12> /cm<2> to 2E<12> /cm<2> . A main condition regarding to a maximum dopant concentration of the vertical type section 30, 32 is that the concentration of each vertical section is sufficiently low, and a depletion region can spread over a horizontal thickness B of the vertical section 30, 32 to horizontal direction before a horizontal electric field reaches a critical electric field. The thickness of the blocking layer in vertical direction is made thinner than that of vertical direction of an ordinary device. Furthermore, because current flows in the N-type section 32 in vertical direction, the blocking layer has lower resistance than that of ordinary device.
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