| 摘要 |
PURPOSE: To prevent the dielectric breakdown of an insulating film, and increase avalanche resistance, by constituting a second trench deeper than a trench, and forming a Schottky electrode which is in contact with the inner surface of the second trench. CONSTITUTION: In the state that a voltage is applied across a drain electrode 9 and a source electrode 8, a positive voltage higher than or equal to a specific value is applied. A reversed layer is formed on the surface layer of a P-base layer 3 beside the gate electrode 7. An electron current flows from the source electrode 8 to the drain electrode 9 through the reversed layer. In an MOSFET, a second trench 20 is deeper than a trench 5 in the gate part. As the result, when a voltage is applied across the drain electrode 9 and the source electrode 8, and the voltage is increased, avalanche breakdown is generated first at the corner part of the second trench 20, so that avalanche breakdown can be prevented from being generated at the corner part of the trench 5 and a gate insulating film 6 is broken down. |
