A semiconductor integrated circuit having a high withstand voltage TFT and a
TFT
which is capable of operating at high speed in a circuit of thin film transistors
(TFT) and methods for fabricating such circuit will be provided. A gate insulating
film of the TFT required to operate at high speed (e.g., TFT used for a logic circuit)
is relatively thinned less than a gate insulating film of the TFT which is required
to have high withstand voltage (e.g., TFT used for switching high voltage signals).