| 摘要 |
PROBLEM TO BE SOLVED: To reduce the dispersion of high breakdown strength property, by providing a semiconductor device with the first wide and shallow groove around the specified region of one conductivity type provided on a semiconductor substrate, providing it with the second groove narrower than the width of the first groove, and covering the second groove with an electric insulator. SOLUTION: This semiconductor device is provided with a base diffusion region 3 of one conductivity type of thickness D3 on a semiconductor substrate 1, and here, the first groove 7 of a wide and shallow mesa groove of W1 in width and D1 in thickness is made around the specified region of the base diffusion region 3. Then, in the region of the first groove 7, a second groove 7' narrower than the width of the first groove 7 of W2 in width and D2 in thickness is made. Furthermore, the second groove 7' is covered with an electric insulator 9, and for the topside of the electric insulator 9, the center is bulged in dome shape, and at the section where the topside contacts with the inside periphery of the first groove 7, a section 9' in recess form is made of the topside of the electric insulator 9 and the inside periphery of the first groove 7. |
