A semiconductor device having high TFT characteristics is realized. In a pixel matrix circuit of an AM-LCD, a lower electrode of a storage capacitor is made to include an element in group
and a catalytic element used for crystallization, so that its resistance is reduced. Further, a dielectric of the storage capacitor is made thin, so that capacity can be secured without increasing an area for formation of the capacitance. Thus, it becomes possible to secure sufficient storage capacitor even in the AM-LCD having a size of 1 inch or less in diagonal without lowering an opening ratio.