Power MOSFET transistor and Schottky diode

摘要

A power MOSFET transistor (2) and a Schottky diode (5) having a low resistance and a high breakdown voltage are provided. When the bottom portion of a narrow trench (20,53) having the shape of a rectangular parallelepiped is filled with a semiconductor (22,57) grown by epitaxial method, a {1 0 0} plane is exposed at the sidewalls of the narrow trench. The semiconductor is epitaxially grown at a constant rate on each sidewall of the narrow trench; thereby, creating a filling material with no voids present therein. The concentration and width of the filling material are optimized. This allows the portion located between the filling materials in a drift layer (12,52) to be completely depleted when the filling material is completely depleted; thereby, making it possible to establish an electric field having a constant strength in the depletion layer extending in the drift layer.