| 摘要 |
An interlayer insulating film (7), which is formed of a silicon oxide film containing phosphorus such as PSG and BPSG, is provided on a first main surface of an n--type drift layer (1) so as to cover a gate electrode (6) that constitutes a MOS gate structure. A protective film (10) is provided on the surface of the interlayer insulating film (7) so as to cover the interlayer insulating film (7). The protective film (10) is formed of a material that has a smaller diffusion coefficient of mobile ions than the interlayer insulating film (7). A front surface electrode (9) that is in contact with a p-type base region (2) and an n+-type region (3) is provided on the surface of the protective film (10). Diffusion of mobile ions coming into the vicinity of the gate electrode (6) from the front surface electrode (9) side is able to be suppressed by the protective film (10), which is provided between the interlayer insulating film (7) and the front surface electrode (9), so that ionic contamination is able to be prevented. Consequently, a semiconductor device is able to be prevented from breakdowns and operational failures. |
