| 摘要 |
PURPOSE:To improve a controllable current by increasing the effective withstand voltage of a junction between a p-base region and a cathode region by contriving that the cathode region become deeper than the center at the edge part wherein the cathode region contacts an etched region. CONSTITUTION:An anode region 2, an n-base region 1, and the p-base region 3 are formed as conventional. But, for this, before diffusing an n type layer of a high concentration, thereafter, a part of the p-base region is etched, and thus a groove 18 is formed. Afterwards, the n type layer of a high concentration is formed, and a cathode region 14 is isolation-formed by selective etching with a depth over it. The different point from that of conventional one is that the deep cathode part 14a is formed at the edge of the cathode. Thereafter, metallic electrodes 5, 6, and 7 are formed. The junction J3 at the edge 14a of the cathode edge is formed at a region of a p type low impurity concentration of the p-base region, therefore the junction has a reverse withstand voltage higher than at the center. |
