| 摘要 |
PROBLEM TO BE SOLVED: To secure necessary withstand voltage without deteriorating an element characteristic by providing a first conduction-type semiconductor substrate with high resistance, which has a recess in either a first or second main face and a power semiconductor element having electrolytic relaxation structure in an area where the recess of the semiconductor substrate is formed. SOLUTION: The recess is formed on the surface of a first n-type cathode layer 1 with high resistance. The first p-type anode layer 2 is selectively formed on the surface of the base part of the recess. The second P-type heavily doped anode layer 3 is selectively formed on the surface of the first p-type anode layer 2. P-type lightly doped reserved layers 4, which have electrolytic relaxation structures, are formed around the first p-type anode layer 2 by bringing them into contact with the layer 2. N-type heavily doped channel stopper layers 5 are formed at outer sides on the surface of the n-type cathode layer 1 by detaching them from the p-type reserved layers 4 by prescribed distances. Thus, the deterioration of the element characteristic can be prevented and the semiconductor element of high withstand voltage can be realized. |
