A thin-film semiconductor device having a CMOS inverter comprising a pair of n-type and p-type thin-film transistors, wherein the gate electrode of at least one of the paired thin-film transistors comprises a plurality of gate electrode sections spaced apart along the channel length. The channel region of the n-type thin-film transistor is doped with p-type impurities. This structure serves to reduce the leakage current and maintain high OFF resistance for a high source-drain voltage. Further, since a good symmetry of characteristics is maintained between the n-type and p-type thin-film transistors that constitute the CMOS inverter, no appreciable bias is caused in the output voltage of the CMOS inverter.