Silicon wafers become semitransparent at room temperature and at wavelengths more than 1.1 pim. Silicon wafers with an oxide film layer are also semitransparent because the extinction coefficient of the film optical constants is negligible at visible and infrared wavelengths. We experimentally studied optical properties such as emissivity, reflectivity and transmissivity of silicon wafers with and without oxide films to devise a new non-contact method of temperature measurement that is applicable to semitransparent silicon wafers near room temperature. The proposed method which is constituted from two blackbodies and p-polarized optical components showed the accuracy of ±I1 K in the temperature range from 313 to 343 K using a radiometer with an InSb sensor at a wavelength of 4.7 ± 0.1 ptm for silicon wafers with low resistivity, irrespective of changes of oxide layer thickness. The method is, however, unable to apply to the measurement near room temperature for silicon wafers with resistivity over 0.1 Qcm because of their emissivities are extremely small.
Emissivity and transmissivity of a silicon wafer were studied during the growth of thin oxide films from the viewpoint of spectral, directional and polarized characteristics of thermal radiation. Experimental results were mostly coincident with simulated results. By using a simulation model to estimate the optical properties of silicon wafers, a direct relationship was found between the ratio of p-to s-polarized radiance and the polarized emissivity under specific conditions. This relationship was experimentally confirmed at high temperatures (> 900 K). On the basis of these results, the present study proposes a new radiation thermometry technique that can measure the temperature and spectral emissivity of a silicon wafer at a wavelength of 0.9 µm and at moderately high temperatures, irrespective of the variation in emissivity with oxide film thickness.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.