An image sensor includes a logic region and an APS region having a first gate electrode, a photo-detector, a first protecting layer, first spacers, and a second protecting layer. The first gate electrode is formed over a semiconductor substrate. The photo-detector is formed to a side of the first gate electrode within the semiconductor substrate. The first protecting layer is formed over the first gate electrode and the photo-detector. The first spacers are formed over the first protecting layer to the sides of the first gate electrode. The second protecting layer is formed over the first protecting layer and the spacers. The first and second protecting layers are for preventing a contaminant from reaching the photo-detector.