AMORPHOUS SILICON THIN FILM AND MANUFACTURING METHOD OF POLYSILICON THIN FILM USING THE SAME

摘要

PROBLEM TO BE SOLVED: To prevent changes of crystallinity of an a-Si thin film against ELA irradiation energy density by specifying the a-Si thin film suitable for the ELA. SOLUTION: A heat treatment of an a-Si thin film, whose thickness is 40 nm-80 nm and whose optical band gap is not less than 1.80 eV and not more than 1.88 eV, is carried out in a temperature not lower than 400 deg.C but not higher than 600 deg.C in nitrogen or inert gas atmosphere so that dehydrogenation can be realized, and that the optical band gap can be not less than 1.68 eV but not more than 1.72 eV. Thus, the change of the crystallinity of the a-Si thin film with respect to ELA energy density is made small, and thus the crystallinity of a poly-Si thin film can be controlled easily.