| 摘要 |
PROBLEM TO BE SOLVED: To reduce on resistance by injecting holes as minority carriers to a drift layer by forming a second conductivity type impurity diffusion region electrically connected to a gate electrode onto the surface of the drift layer between second conductivity type impurity diffusion regions. SOLUTION: Positive threshold voltage is applied to gate electrodes 7 for bringing a vertical type MOS transistor to a conductive state in the vertical type MOS transistor. That is, when positive voltage is applied to the gate electrodes 7, holes as minority carriers are injected to a drift layer 2 from a P-type impurity diffusion region 23 because the P-type impurity diffusion region 23 is connected to the gate electrodes 7. Since a section, into which holes are injected, in the drift layer 2 is operated by a bipolar mode by holes and electrons in a conductivity modulation region, into which a current is flowed by holes and electrons, a voltage drop is lowered. Accordingly, since the MOS transistor is operated in the bipolar mode, by which the current is flowed by electrons and holes, on resistance can be reduced. |
