| 摘要 |
PROBLEM TO BE SOLVED: To improve the operating withstand voltage of a high-withstand voltage MOS transistor. SOLUTION: An n-type drain layer 4b is formed on the surface of a p-type semiconductor substrate 1 in a state that the layer 4b is overlapped under a gate electrode 5 so that the partial surface of the n-type drain layer 4b under the gate electrode 5 is depleted, when a drain-source voltage Vds higher than a gate-source voltage Vgs applied to the gate electrode 5 is impressed upon the n-type drain layer 4b. Consequently, the channel current Ie flowing to the MOS transistor tends to flow through the n-type drain layer 4b below the depletion layer 7 by avoiding the striking of the electric field concentrated portion of the surface at the end of the n-type drain layer 4b. Therefore, the current Isub of the semiconductor substrate 1 is reduced and the operating withstand voltage of the MOS transistor is improved. COPYRIGHT: (C)2005,JPO&NCIPI
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