| 摘要 |
PROBLEM TO BE SOLVED: To provide the new structure and manufacturing method of a trench MOS for reducing feedback capacity. SOLUTION: This semiconductor device is provided with a second conductivity-type base layer 3, formed on the surface of a first conductivity-type semiconductor substrate 1 or a first conductivity-type semiconductor layer 2, a first conductivity-type source layer 8 selectively formed on the surface of the second conductivity-type base layer 3, a trench groove 4 to the second conductivity-type base layer 3 through the first conductivity-type source layer 8, first and second gate electrodes 6 respectively formed through a gate oxidized film 5 on the inner side wall surface of the trench groove 4, an insulation film 10 formed between the first and second gate electrodes and a first conductivity- type electric field mitigation layer 7 provided between the trench groove 4 and the first conductivity-type semiconductor substrate 1 or the first conductivity-type semiconductor layer 2 in contact with both. A channel is disposed in the vertical direction which is to be the depth direction of the trench groove 4 and the joining depth of the second conductivity-type base layer 3 is deeper than the trench groove 4.
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