A semiconductor device having high reliability, in which TFTs with
appropriate structures for the circuit functions are arranged, is
provided. Gate insulating films (115) and (116) of a driver TFT are
designed thinner than a gate insulating film (117) of a pixel TFT in a
semiconductor device having a driver circuit and a pixel section on the
same substrate. In addition, the gate insulating films (115) and (116) of
the driver TFT and a dielectric (118) of a storage capacitor are formed
at the same time, so that the dielectric (118) may be extremely thin, and
a large capacity can be secured.