This paper presents a Monte Carlo model for prediction of the radiative properties of semitransparent silicon wafers with rough surfaces. This research was motivated by the need of accurate temperature measurement in rapid thermal processing (RTP) systems. The methods developed in this paper, however, can be applied to various semitransparent materials, such as diamond films. The numerically obtained bidirectional reflectance distribution function (BRDF) showed a similar trend as the experimental data. Furthermore, a higher angular resolution can be achieved by simulation than by experiments. The bidirectional transmittance distribution function (BTDF) can also be computed in the same run for semitransparent wafers. Other spectral radiative properties (such as the directional-hemispherical transmittance and reflectance, the emittance and the absorptance) under various surface conditions were computed at various temperatures. The results can help gain a deeper understanding of the radiative behavior of semitransparent materials and may be applied to various fields.

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