| 摘要 |
PROBLEM TO BE SOLVED: To provide a guard ring structure of a higher breakdown voltage. SOLUTION: This device is constituted, as a reach-through type, of at least a first guard ring region 1 so formed in the shape of a ring at a specified distance from the main region 20 as to surround the main region 20 and a second guard region 2 so formed in the shape of a ring at a specified distance from the first guard ring region 1 as to surround the first guard ring region 1. For the conditions for avaranche breakdown of the main junction face, the distance between the first guard ring region 1 and the second guard ring region 2 is set smaller than the one between the main region and the first guard ring region 1 so that the maximum value of a field intensity at a junction face between the first guard ring region 1 and a drift region 5 may be 85% of or less than that in the main junction face. |
