fig3 i and grain boundaries 214 are formed in the polycrystalline silicon layer 212 a the polycrystalline silicon layer formed according to the process of the present invention is illustrated in fig4 a in fig4 a the regions between two dotted lines indicate the location of the seeds 210 while the solid lines indicate the grain boundaries 214 respectively afterwards thin film transistors are formed by any of suitable manufacturing processes which are not intended to be described redundantly herein in fig4 b the hatched portions indicate the location of the thin film transistors and the source electrodes s the gate electrodes g the drain electrodes d and thus channels of the thin film transistors are shown as previously described the energy density of the pulse laser for example an excimer laser effective for forming a polycrystalline silicon layer with good electrical property is confined to a narrow range the improper energy density is likely to result in the formation of microcrystalline silicon instead of desired polycrystalline silicon or result in non uniform grain size of the recrystallized polycrystalline silicon layer according to the present invention seeds are additionally provided between the substrate and the amorphous silicon layer prior to the formation of the amorphous silicon layer accordingly when a certain energy density of excimer laser required for melting the amorphous silicon layer in the prior art or even if a little more intense excimer is applied to the amorphous silicon layer of the present invention for the same period of time the seeds are protected from being molten away in other words the energy density range of an excimer laser suitable for melting and recrystallizing the amorphous silicon layer into the polysillicon layer can be broadened referring.