a method for manufacturing a semiconductor device such as a thin film transistor using a crystal silicon film is provided . the crystal silicon film is obtained by selectively forming films , particles or clusters containing nickel , iron , cobalt , ruthenium , rhodium , paradium , osmium , iridium , platinum , scandium , titanium , vanadium , chrome , manganese , copper , zinc , gold , silver or silicide thereof in a form of island , line , stripe , dot or film on or under an amorphous silicon film and using them as a starting point , by advancing its crystallization by annealing at a temperature lower than a normal crystallization temperature of an amorphous silicon . a transistor whose leak current is low and a transistor in which a mobility is high are obtained in the same time in structuring a dynamic circuit having a thin film transistor by selectively forming a cover film on a semiconductor layer which is to become an active layer of the transistor and by thermally crystallizing it thereafter .