| 摘要 |
PROBLEM TO BE SOLVED: To provide a semiconductor device improving withstand voltage by a relatively simple method. SOLUTION: In this semiconductor device, a main surface 6 is divided into a higher upper stage 18 and a lower stage 20 by means of a step. The semiconductor device includes: a semiconductor substrate 5 having an n-type drift layer 13 on the main surface 6 side; a p-type base layer 14 selectively arranged on the upper stage 18 side of the main surface 6 and constituting an element region 8; a plurality of p-type guard ring layers 16 located on the main surface 6 side around the element region 8, each having constant distances from the upper stage 18 and the extension surface of the upper stage 18 to the bottom face, having a p-type impurity concentration higher than that of the p-type base layer 14, surrounding the p-type base layer 14, and forming ring-like shapes separately from one another; a surface oxide film 25 formed on the main surface 6 around the element region 8; and field plate electrodes 31 electrically connected to the respective p-type guard ring layers 16 through the surface oxide film 25. At least one of the p-type guard ring layers 16 faces the lower stage 20 of the main surface 6. COPYRIGHT: (C)2011,JPO&INPIT |
