Laser-induced temperature rise in anisotropic substrates

Abstract

Laser-induced temperature rise in anisotropic substrates has been investigated by solving the heat equation in anisotropic media. A model was derived to calculate the laser-induced temperature in anisotropic substrates. It is found that the heat equation in anisotropic media can be simplified to a heat equation in isotropic media by coordinate transformation. The anisotropy of the media can then be reflected by heat source transformation. The results reveal that the laser-induced temperature rise can be significantly affected by the anisotropy of the substrate. The thermal conductivity change along the Z direction (downward into the substrate) will affect the temperature rise more significantly than that along the X and Y directions (parallel to the substrate surface). The anisotropy in thermal conductivity not only affects the peak temperature rise, but also affects the shape of the temperature profile.