| 主权项 |
1. A semiconductor device comprising:
a first semiconductor layer of a first conductivity type; a second semiconductor layer of a second conductivity type having a plurality of trenches, the second semiconductor layer being disposed on the first semiconductor layer; and a plurality of embedded electrodes buried in the plurality of trenches of the second semiconductor layer and a wiring layer disposed on the second semiconductor layer, wherein the first semiconductor layer and the second semiconductor layer constitute a PN diode, the second semiconductor layer includes a first layer disposed on the first semiconductor layer, a second layer disposed on the first layer and having a higher impurity concentration than the first layer, and a third layer which is a high concentration impurity region disposed on the second layer and having a higher impurity concentration than the second layer, the plurality of trenches are formed so as to penetrate the third and second layers, each region between neighboring trenches serves as a channel, to interrupt the channel, each region between the neighboring trenches is blocked by respective depletion layers formed around the neighboring trenches, whereas to open the channel, at least a part of the depletion layer formed around each trench is deleted, each of the embedded electrodes is disposed on an inner surface of a respective one of the trenches via an insulator film, disposed on each embedded electrode is an upper insulator film buried in a respective one of the trenches to a vicinity of respective upper end portion of the trench, the upper insulator film having a thickness at least as large as a thickness of the high concentration impurity region, and the channel has a width equal to a width of the second layer and to a width of the third layer. |
