Two-Dimensional Transient Analysis of Absorbing Thin Films in Laser Treatments

Abstract

In this paper the transient coupled conductive-radiative field, due to a laser heat source impinging on a thin film deposited on a substrate, has been solved in the hypothesis of one dimensionality of the optical field and of two dimensionality of the thermal field. Results have been obtained with the matrix method for the optical field and the finite volume method for the thermal field. The results show that when the investigation is localized to the center of the spot, the one-dimensional model describes the thermal field quite well. Instead, if knowledge of the temperature is required elsewhere, the two-dimensional model is needed. The investigation herein presented shows that for low-conductivity materials (a–Si) the temperature peaks are placed inside the thin film for the absorption function distribution, determined by interference phenomena. [S0022-1481(00)01301-3]