Semiconductor device and method of manufacture thereof

A semiconductor device, comprising:

• a semiconductor layer of a first conductive type;
• a first semiconductor region of a second conductive type on the semiconductor layer;
• a first insulating film and a control electrode disposed in a trench formed in the semiconductor layer through the first semiconductor region, the first insulating film being formed on an inner surface of the trench and the control electrode being formed on the first insulating film;
• and
• a second insulating film on the control electrode, the upper surface of the second insulating film being lower than an upper end of the first insulating film.

A semiconductor device, comprising:

• a semiconductor layer of a first conductive type;
• a first semiconductor region of a second conductive type on the semiconductor layer;
• a first insulating film and a control electrode disposed in a trench formed in the semiconductor layer through the first semiconductor region;
• a second insulating film on the control electrode;
• a second semiconductor region formed on the first semiconductor region on an opposite side of the first insulating film from the control electrode;
• a third semiconductor region formed above and connected to the first semiconductor region;
• a main electrode in contact with the second semiconductor region and the third semiconductor region and extending into a contact hole formed between adjacent control electrodes to make contact with the third semiconductor region;
• and
• a conductive layer on either side of the main electrode that extends into the contact hole and above the second semiconductor region.