pressure of 1 to 1 5 torr at a temperature of about 330 to about 430 u00b0 c further the lpcvd is performed using si 2 h 6 ar under a pressure of 0 2 to 0 4 torr at a temperature of about 400 to about 500 u00b0 c further a buffer layer such as a silicon nitride sinx layer or a silicon oxide sio 2 layer may be further formed on the substrate prior to depositing the amorphous silicon layer in order to prevent contaminants or the like created in the substrate from diffusing into the silicon layer or enhance interface characteristics between the silicon layer and the substrate the amorphous silicon or the silicon layer 12 that contains a great quantity of amorphous silicon is then annealed as shown in fig1 b at this time when the silicon layer is heated the amorphous silicon is not melt because at the same time the amorphous silicon is cooled and crystallized into the polycrystalline silicon using the solid phase crystallization method the polycrystalline silicon is then patterned to form a semiconductor layer 12 a in the present invention a rapid thermal annealing rta process or a typical high temperature annealing process in a furnace is used as the annealing process conventional annealing is carried out in an inert n 2 or o 2 atmosphere while the annealing in the present invention is carried out in an h 2 o atmosphere the annealing in the h 2 o atmosphere.