| 摘要 |
PURPOSE: To lower the ON-voltage of a device by a method wherein a second type carrier current has a polarity opposite to the polarity of a second conductivity type drain layer and the ratio of the second type carrier current in a total current is increased to increase the accumulation of the second type carrier current on the source side. CONSTITUTION: A trench 7 is formed in the surface of an n-type silicon layer 3 between an n-type buffer layer 4 and a p-type base layer 11. An n-type bypass layer 12 is so formed in the n-type silicon active layer 3 under the trench 7 as to be brought into contact with a silicon oxide film 2. Therefore, a positive hole current applied to a source electrode 9 can be reduced by the trench 7. On the other hand, an electron current can be applied to a device through the n-type bypass layer 12 and the reduction of the electron current caused by the trench 7 can be suppressed. With this constitution, the ratio of the electron current in a total current can be elevated and the accumulation of the electron current on the source side is increased, so that the ON-voltage of the device can be lowered. |
