Role of thermal conductivity and optical absorption coefficient of amorphous silicon in pulsed laser melting

Abstract

An expression showing the temperature dependence characteristics of the thermal conductivity of amorphous silicon is examined using the heat flow model to calculate the melting threshold energy Eth for various laser conditions. The results agree well with the experimental data for excimer and Nd:YAG frequency-doubled laser irradiation but not with those for ruby laser irradiation. Various factors which might contribute to the discrepancy between experimental and calculated Eth values for ruby laser irradiation are discussed. We conclude that this discrepancy is probably due to the inaccuracy of the experimental value for the optical absorption coefficient of a ruby laser that we used in the calculations. © 1988.