We have investigated PtHf silicide formation utilizing a developed PtHf-alloy target to realize low contact resistivity for the first time. A 20 nm-thick PtHf-alloy thin film was deposited on the n-Si(100) by RF magnetron sputtering at room temperature. Then, silicidation was carried out by rapid thermal annealing (RTA) system at 450-600^°C/5 min in N₂/4.9%H₂ ambient. The PtHf-alloy silcide, PtHfSi, layers were successfully formed, and the Schottky barrier height (SBH) for electron of 0.45 eV was obtained by 450^°C silicidation. Furthermore, low contact resistivity was achieved for fabricated PtHSi such as 8.4x10^-8 Ωcm² evaluated by cross-bridge Kelvin resistor (CBKR) method.