TEMPERATURE DISTRIBUTIONS PRODUCED IN MULTILAYER STRUCTURES BY A SCANNING CW LASER-BEAM

Laplace-transformed Green's function solutions to linear heat equations are derived for multilayered structures. An analytic expression for linear temperature distribution produced by a scanning CW elliptical Gaussian laser beam is given in a double integral form and its numerical results are presented. In conjunction with the linear temperature formula, a nonlinear algorithm has been developed in order to incorporate temperature-dependent thermal diffusivity, conductivity, and surface reflectivity. The temperature distributions for the Si/SiO2/Si structure are calculated, including effects of melting of Si. From comparison between the calculation and a measurement on the melting width, it is found that the excess energy absorbed above the melting temperature is spatially redistributed on melting.