Determination of thickness and porosity of porous silicon layer using photoacoustic technique

The thickness of thin porous layers of silicon samples and their varying porosity have been determined using photoacoustic technique (PA). The measured values of the effective thermal diffusivity (alpha(eff)) and effective thermal effusivity (e(eff)) were exploited to determine the thickness of porous silicon (p-Si) film using the effective layer model. Also the determined alpha(eff) together with the two-layer model were used to obtain the thermal diffusivity of the p-Si layer only. Using Maxwell-Rayleigh model, the porosity percentage for the different samples were determined and compared to the results obtained by scanning electron microscope (SEM) with 10 \% variations.