| 摘要 |
PROBLEM TO BE SOLVED: To improve a breakdown strength with low on-resistance while a sufficient element breakdown voltage characteristic is held for a process variation at the time of ion implantation in a peripheral breakdown voltage structure, independent of crystal plane direction of a substrate.SOLUTION: A vertical high breakdown voltage semiconductor device includes a first conductive type semiconductor substrate (1), a semiconductor layer (2) which is formed on the semiconductor substrate (1) to be first conductivity type and has concentration lower than the semiconductor substrate (1), a second conductivity type semiconductor layer (3) of high concentration which is selectively formed on the surface of the semiconductor layer (2), a base layer (4) of second conductivity type and low concentration, formed on the semiconductor layer (2) and the second conductivity type semiconductor layer (3), and a first conductive type source region (5) which is selectively formed on a surface layer of the base layer (4). At an element peripheral part, a part of the second conductivity type semiconductor layer (3) is removed, and then, on the surface of the semiconductor layer (2) whose concentration is lower than the semiconductor substrate (1), a plurality of second conductivity type layers (11 and 12) of low concentration are formed. The second conductivity type layer (11) at the innermost periphery is arranged not to contact to the second conductivity type semiconductor layer (3) and the base layer (4). |
