| 摘要 |
In a static induction type semiconductor device comprising a semiconductor region having one conductivity type and a low impurity concentration and gate regions having an opposite conductivity type and a high impurity concentration formed in the semiconductor region to thereby define a channel region between these gate regions, there is provided a subsidiary semiconductor region having the one conductivity type and a relatively high impurity concentration either around each gate region to leave an effective channel region in the semiconductor region, or adjacent to the effective channel region in the entire channel region on the drain side. By so constructing the device, this effective channel region has a relatively low potential difference even when the channel region is completely depleted, and provides a relatively wide current path. The subsidiary semiconductor regions establish a relatively high potential difference near the gate regions so that the distance between the gate regions can be made substantially small. In case the subsidiary semiconductor regions are provided around the gate regions, the built-in potential at the junction will become large so that, even at the time of forward biasing, the minority carrier injection from the gate to the channel will become small. Also, this composite channel structure can be effectively applied to recessed gate device and split gate device as well.
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