Method for fabricating a TFT

摘要

To fabricate a crystalline semiconductor film with controlled locations and sizes of the crystal grains, and to utilize the crystalline semiconductor film in the channel-forming region of a TFT in order to realize a high-speed operable TFT. A translucent insulating thermal conductive layer 2 is provided in close contact with the main surface of a substrate 1, and an insular or striped first insulating layer 3 is formed in selected regions on the thermal conductive layer. A second insulating layer 4 and semiconductor film 5 are laminated thereover. The semiconductor film 5 is first formed with an amorphous semiconductor film, and then crystallized by laser annealing. The first insulating layer 3 has the function of controlling the rate of heat flow to the thermal conductive layer 2, and the temperature distribution difference on the substrate 1 is utilized to form a single-crystal semiconductor film on the first insulating layer 3.