Study of the radiative properties of silicon-based materials for thermal processing and control

Radiative properties are important for radiometric temperature measurements and thermal control during materials processing. Although there have been extensive studies of the radiative properties of silicon and related materials, existing model expressions do not cover some important spectral and temperature ranges of practical interests. In the present study, selected optical models are summarized and used to calculate the optical constants of lightly doped silicon, with necessary extrapolations. The effect of coatings covering one or both sides of a smooth silicon wafer is studied at room temperature as well as at elevated temperatures. Furthermore, the influence of surface roughness on the radiative properties of semitransparent wafers with a dielectric coating is also examined. This work demonstrates the need for a more thorough investigation, with the assistance of high-accuracy measurements, of the radiative properties of silicon-based materials at elevated temperatures.