| 摘要 |
PURPOSE:To reduce the voltage drop when a thyristor is conducted by forming a step in a p type emitter region and forming the width of the n type base region thin in the element forming portion and thick in the mesa forming part. CONSTITUTION:A recess 11 (a depth of deeper than 10mum) is formed by etching the main surface of the side to be formed with a p type emitter region 5a of the element forming part of an n type wafer substrate. Then, p type emitter region 5a and p type base region 4 are so formed on both main surfaces of the wafer substrate that the width of the region 5a is thicker than the width of the base 4, and the residue of the wafer substrate is formed as an n type base region 3. Thereafter, n type emitter region 6 is formed at the predetermined part of the surface part of the region 4, and n type base region 3 and the mesa groove 7 reaching the recess 11 are formed from both main surface of the wafer substrate between the element forming parts and between the element forming part and the peripheral edge of the wafer substrate. |
