| 摘要 |
PURPOSE:To contrive the improvement of breakdown strength of the drain of a transistor by a method wherein the concentration of the offset part of the transistor and the concentration of stopper part, by which the threshold voltage of a parasitic transistor of the transistor is decided, are changed. CONSTITUTION:The concentration of N-type diffused layers 107 and 109 and the concentration of P-type diffused layers 106 and 110 are different from each other. For example, when the above layers are formed by implanting phosphorus in a P-type substrate 101 on 100KeV and in 5X10<2>cm<-2>, the offset part of a P-channel transistor is formed by implanting boron on 25KeV and in 1X10<13>cm<-2>, for example, and a part, which is used as a channel stopper to prevent a parasitic channel, of an N-channel is formed by implanting boron on 25KeV and in 1X10<14>cm<-2>, for example.
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