| 摘要 |
PROBLEM TO BE SOLVED: To provide a semiconductor device in which breakdown voltage characteristics are enhanced without increasing the thickness of element significantly. SOLUTION: The semiconductor device comprises a lightly doped semiconductor layer 2 having a trench A shallower than the thickness thereof. A trench B having depth equal to or deeper than the thickness of the semiconductor layer 2 is made on the outer circumference of the shallow trench A. A heavily doped buried layer 4 having conductivity type opposite to that of the semiconductor layer 2 is formed on the bottom of the shallow trench A. The buried layer 4 is formed with uniform thickness toward the outer circumferential direction of the shallow trench A. |
