Bidirectional Reflectance Measurement of Microstructural Silicon Surfaces

Knowledge of the bidirectional reflectance of silicon wafers is needed for the modeling prediction of the emitted and reflected radiation detected by radiometric thermometers, so that these instruments can be properly employed in industrial applications, such as rapid thermal processing chambers [1]. In a previous study [2], the bidirectional reflectance was observed to be sensitive to the surface roughness and coating configuration. For a typical silicon wafer, the surface could be polished, thin-film coated, randomly rough, or patterned. The characteristic parameters of the surface topography fall into the microscale or even nanoscale range. The present paper focuses on the bidirectional reflectance measurement of silicon wafers with thin-film coatings on their randomly rough sides. The reflectance distribution out of the incidence plane is also measured for the sake of a thorough characterization of surface scattering.