Detectable wavelength range and the responsivity of PtSi Schottky diode IR detector is improved by schottky diode barrier lowering using ion implantation. The ion implantation energy is decided from the condition that the peak impurity concentration was placed at the interface of PtSi-Si. From I-V measurement, the barrier height is calculated. But ideality factor is larger than one indicating that the calculated barrier height is not always accurate. The calculated values of series resistance from the I-V measurement is $10^3\sim4\times10^4$Ω. The reason for large series resistance comes from the fact that the thickness of PtSi layer is too thin(10 nm). IR response current for 400℃ black body radiation increases with the implantation dose indicating that higher implantation dose gives lower barrier height which in turn gives higher responsivity.