In this study, a polycrystalline silicon (poly-Si) film layer for micro thermoelectric generators (TEGs) was optimized by using Taguchi methods. An experimental plan using an orthogonal array $L_9;(3^4)$ is described. The fabrication process of the thermoelectric poly-Si films layer is presented in detail. The P-type poly-Si films were fabricated on a tetra ethoxy silane (TEOS) layer with a supporting Si wafer. The thermoelectric properties, Seebeck coefficient and electrical conductivity were measured, including the transport properties such as the hall coefficient, hall mobility and carrier concentration. The design parameters were optimized based on the experimental results. Using the optimum values, a p-type poly-Si films layer was fabricated and its power factor was measured. The measured power factor was $541;{mu}Wm^{-1}K^{-2}$, which was better than the predicted value of $221;{mu}Wm^{-1}K^{-2}$.