Image sensors and methods of manufacturing an image sensor are disclosed. A disclosed photo diode may receive short wavelength light in its depletion region without exhibiting defective phenomenon such as noise and dark current. In the illustrated example, this performance is achieved by forming a trench type light-transmission layer to occupy a major surface of the photo diode so as to reduce the area available for defects on the surface of the semiconductor substrate. As a result of this reduction, the depletion region formed upon the operation of the sensor may extend toward the surface of the semiconductor substrate without concerned for defects. The image sensor may be manufactured without forming a blocking layer in connection with a silicide layer.