The diffusion of P in Si–TaSi2eutectic and silicon single crystal specimens was investigated at a concentration of about 1019atoms cm−3in the temperature range of 767–1227 °C. No definite distinction can be made between diffusion of P in the eutectic structure and in silicon. A nonlinear Arrhenius plot was obtained, indicating a P diffusion enhancement at the lower temperature range. From the linear portion of the Arrhenius line drawn through all the experimental points, an activation energy and pre‐exponential factor of 3.75 eV and 5.7 cm2 s−1were derived, respectively.