The current-voltage characteristics of PtSi/p-Si Schottky barrier diodes were investigated in the temperature range of 85-136K and their barrier height (Φ_b), ideality factor (n) and series resistance (R_s) were found to be strongly temperature-dependent. While n decreases, Φ_b increases with increasing temperature and the conventional activation energy plot deviates from linearity. These discrepancies from ideal thermionic emission theory is attributed to Schottky barrier inhomogeneities and the Schottky barrier inhomogeneities are shown to obey a single Gaussian distribution with a mean value of 0.4548eV and a standard deviation of 0.0607eV. The modified activation plot which takes into account the barrier height variations through the Gaussian distribution is acceptably linear and gives ($\overline{\phi_b}$) and A^* as 0.4546eV and 31.47Acm^-2K^-2 respectively.