| 摘要 |
PURPOSE:To avoid field concentration at a circumferential lower side of a guard ring and increase the withstand voltage of a semiconductor element by arranging a circular recess groove surrounding the guard ring. CONSTITUTION:In a planar-type semiconductor device composed of an anode layer 2, a guard ring layer 3, an anode electrode 4, a cathode layer 5 and the like, a circular recess groove 12 is formed so as to surround a guard ring 3 at its circumferential part. Such a configuration prevents field concentration at the circumferential lower side of the guard ring and accordingly can increase the withstand voltage of an element to a great extent. Furthermore, the number of the above guard ring and the circular recess groove is not limited to a pair of them but it may be as well to prepare plurality of pairs of them. In such a case, however, the more the recess grooves are situated to outer sides, it is necessary that the more their sectional areas are reduced in size. Thus, this approach helps mitigate the above field concentration and increase the withstand voltage of the above element. |
