| 摘要 |
PROBLEM TO BE SOLVED: To reduce noise in a semiconductor device which includes a depression N channel transistor. SOLUTION: The depression N channel transistor has a drain region 7, formed into a circular shape and a gate region 5 whose outer periphery is in the circular shape is arranged so that it surrounds the drain region. A source region 71 is disposed outside the gate region so that it surrounds the drain region, and the source region is detached from an oxidized film for element separation 3 by a previously stipulated distance. A P<+> diffusion layer 8 is formed outside the source region and the P<+> diffusion region detaches the source region from the oxidized film for element isolation by the previously predetermined distance. A contact hole 10 is formed in the P<+> diffusion layer which is in common with the source region, and the gate region and the drain region are arranged concentrically.
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