SEMICONDUCTOR DEVICE HAVING FIRST SECOND AND THIRD NONCRYSTALLINE FILMS SEQUENTIALLY FORMED ON INSULATING BASE WITH SECOND FILM HAVING THERMAL CONDUCTIVITY NOT LOWER THAN THAT OF FIRST FILM AND NOT HIGHER THAN THAT OF THIRD FILM AND METHOD OF MANUFACTURING SAME

摘要

PURPOSE: To manufacture a thin-film transistor(TFT) of fast operation at a high yield. CONSTITUTION: A filed effect transistor(TFT) is formed at a polycrystal semiconductor thin-film 4 provided on the surface of an insulating substrate 1. Here, a first thin-film (silicon oxide film) 2 is formed on the surface of the insulating substrate, and a second thin-film (silicon nitride film) 24 whose heat conductivity is higher than the first thin- film is formed on the first thin-film. The second thin-film is selectively removed to leave a part corresponding to a gate electrode formation region. Then, an amorphous semiconductor film (amorphous silicon thin-film) 3 whose heat conductivity is higher than the second thin-film is formed on the first and second thin-films and it is converted into a polycrystal semiconductor thin-film 4 under the heat of laser 5. Te crystal particle size at the channel part formed by the polycrystal semiconductor thin-film is large in crystal size, even and flat because of the presence of the second thin-film. The thin-film transistor allows fast operation. The reproducibility in crystal formation at the channel can be obtained with high-quality of TFT as well as high yield.