Emissivity of Semiconductor Substrate in Non-equilibrium Environment

摘要

It is frequently concluded that the emission of semiconductor materials is only surface effect. This opinion probably originates from our knowledge of heat transfer as used in mechanical engineering where most of applications are dealing with opaque bodies. The microscopic interpretation of the radiation processes in semiconductors is suggesting that the total emission of a body is the sum of induced emission and spontaneous emission. In many application of RTP, the semiconductor wafer is not in thermal equilibrium with the radiation field. The wafer temperature is usually a much lower than temperature of the source of the irradiation. Thus the environment would lead to a different amount of stimulated emission and accordingly to a total emissivity different from the one found in thermal equilibrium.