PURPOSE: To stabilize substrate potential by forming a recessed section to an Si substrate in the vicinity of a transistor for a MOSIC and connecting a power supply line to the recessed section.

CONSTITUTION: An n type Si substrate 1 is isolated by an oxide film 11, a p well 2 is formed, and poly Si gate electrodes 3, 4 are attached onto gate oxide films 9, 10. n type source-drain 5, 6 and p type source-drain 7, 8 are shaped. Recessed sections are formed where near by channels in each FET, a p+ region 12 having low resistance and an n+ region 13 are shaped around the recessed sections in a wide area, and Al electrodes 14 are attached. According to the constitution, the potential of the substrate 1 can be fixed efficiently where near by the channels. Said constitution is also effective to the case of an (n) well CMOSFET similarly.