Modeling of cw laser annealing of multilayer structures

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Abstract
Careful computer modeling can accurately represent the temperature distribution created during laser annealing. In this way a better understanding of the physical processes that contribute to thin film crystallization is achieved, and precise predictions of the effects of various sample geometries on laser annealing are possible. Models of cw laser annealing have always assumed a single homogeneous medium, but practical structures usually consist of several layers of semiconductors, insulators and metals of widely varying thermal and optical properties. This treatment can model an arbitrary number of layers of various thicknesses, each with its characteristic thermal and optical properties. The problem is solved under steady state conditions without phase transitions. A general analytic expression cannot be obtained, but a simple procedure is presented for obtaining the temperature distribution in a given system. Explicit integral expressions are developed for the cases of two and three layers; numerical results are calculated for the Si/glass and Si/SiO2/Si systems.