Semiconductor device, and method of manufacturing the same

A semiconductor device, comprising:

• a first semiconductor layer of a first-conductivity type having a first surface;
• a second semiconductor layer of the first-conductivity type having a second surface contacting the first surface;
• an electrode in the second semiconductor layer contacting the first surface of the first semiconductor layer and a third surface of the second semiconductor layer, the third surface having a first end contacting the first surface of the first semiconductor layer and a second end distal to the first surface;
• and
• a third semiconductor layer having a higher impurity concentration than the second semiconductor layer, the third semiconductor layer disposed between the second semiconductor layer and the electrode, wherein
• an angle between the first surface of the first semiconductor and the third surface of the second semiconductor layer is at least 90 degrees.

A method of manufacturing a semiconductor device, the method comprising:

• forming a first trench in a second semiconductor layer of a first-conductivity type, the second semiconductor layer being disposed on a first semiconductor layer of the first-conductivity type;
• forming a first electrode in the first trench, the first electrode being disposed on an insulating film in the first trench;
• forming a third semiconductor layer of a second-conductivity type on the second semiconductor layer, the third semiconductor layer contacting the insulating film;
• forming a fourth semiconductor layer of the first-conductivity type on the third semiconductor layer, the fourth semiconductor layer contacting the insulating film;
• forming a fifth semiconductor layer of the first-conductivity type on the second semiconductor layer;
• forming a second trench in the fifth semiconductor layer and the second semiconductor layer below the fifth semiconductor layer by etching, wherein an impurity concentration in the fifth semiconductor layer is higher than an impurity concentration in second semiconductor layer;
• forming a second electrode on the fourth semiconductor layer;
• and
• forming a third electrode in the second trench.