Investigation of thermal and optical properties on polysilicon by the photothermal deflection technique

Abstract

In this paper, a method is described to study the geometry and thermal properties of grain boundaries in a polysilicon sample. This method is based on the Photothermal Deflection Technique called “Photothermal Imaging.” In order to be able to heat the sample by a very low laser beam power (2 mW), the sample is immersed in a cell filled with paraffin oil. The comparison of the experimental curves of amplitude and phase of the photothermal signal variations versus the displacement x of the sample to the corresponding theoretical ones allows obtaining thermal properties of the grain boundaries and their dimension.