A method for fabricating CMOS image sensor is provided to obtain images of high quality by enhancing an optical absorbing rate and photoelectric conversion efficiency. A substrate(201) including a pad layer for opening a photosensitive region as a photodiode region is provided. A high temperature oxidation process for the opened photosensitive region is performed. A recess part is formed on the photosensitive region by removing an oxide layer. A SiGe layer(209) is grown on the photosensitive region to increase the optical sensitivity of the recess part. A photodiode ion implantation process for the photosensitive region including the SiGe layer is performed.
