| 摘要 |
<p>PROBLEM TO BE SOLVED: To solve a problem of a trench-type MOSFET such that a withstand voltage of a gate insulation film decreases due to field concentration on a trench corner; and when the gate insulation film is thickened in order to inhibit decrease in withstand voltage, on-resistance increases; and when a thickness of the gate insulation film is constant in a trench, it is difficult to satisfy both of low on-resistance and a high withstand voltage.SOLUTION: In a trench-type SiC-MOSFET manufacturing method, an optical CVD film 6b of the bottom-up fill is used for a part of a gate insulation film in a trench in order to provide a trench-type SiC-MOSFET which satisfies both a low on-resistance and a high withstand voltage. By doing this, the gate insulation film at a bottom face is thicker than the gate insulation film at a lateral face. Specifically, the trench-type SiC-MOSFET is manufactured by: a process of forming a trench on an SiC substrate; a process of forming an insulation film 6b on a bottom of the trench by optical CVD; and a process of forming a gate electrode 7 on the insulation film.</p> |
