Heat Transport Analysis for Flash Lamp Annealing

Abstract

The silicon wafer temperature change during flash lamp annealing is theoretically evaluated. A calculation model is developed on the basis of a finite difference method taking into account various heat transport phenomena, such as heat radiation from a lamp to a silicon surface, reflection at the silicon surface, heat radiation from a hot silicon surface, light absorption in silicon, and thermal conduction. The effect of the light absorption in a silicon wafer on the temperature profile is negligible at the position of ultrashallow junction formation. The largest temperature slope is shown to be formed by flash lamp annealing because of the agreement of the temperature slope obtained by taking into account heat absorption in silicon with that obtained by assuming heat absorption only at the surface, without accounting for the light absorption in silicon. This study further concludes that the surface reflectivity strongly affects the silicon temperature.