width length w l is 10 8 and the thus obtained transfer characteristic is shown in the graph of fig9 meanwhile a threshold voltage v a sub threshold slope mv dec a field effect mobility cm 2 v u00b7 s and a maximum on off current ratio are shown in the following table 1 as can be seen from fig9 and table 1 the physical characteristics of the transistor fabricated by crystallizing an amorphous silicon according to the present invention are substantially same as those of a conventional polycrystalline silicon transistor however in the case of the on of current ratio and the field effect mobility it can be seen that the values of the transistor according to the present invention are greatly enhanced as described above the thermal annealing apparatus according to the present invention can locally heat an amorphous silicon to be crystallized according to a scanning method where a substrate is transferred at the state where linearly focused lamp light is illuminated on a glass substrate accordingly the present invention can crystallize an amorphous silicon uniformly without deformation of a large area transparent glass substrate such as a lcd for tv irrespective of the size of the substrate and without extending the size of the thermal annealing apparatus three dimensionally further in the case where a number.