| 摘要 |
PROBLEM TO BE SOLVED: To solve the problem in the formation of a superjunction based on a buried epitaxial process, that a taper angle of dry etching in trench formation etching generally is adjusted to create a graded column in order to prevent a withstand voltage from getting lowered by a concentration fluctuation in the buried epitaxial layer, but this method makes device design increasingly difficult as the need for high withstand voltage arises.SOLUTION: The present invention pertains to a vertical type power MOSFET having a superjunction based on a buried epitaxial process, in which a concentration in an intermediate substrate epitaxy type column region in each substrate epitaxy type column region constituting the superjunction is raised to be higher than in other regions of the substrate epitaxy type column region. |
