The present disclosure provides a photodiode device, which includes a semiconductor substrate, a well region in the semiconductor substrate of a first dopant type, a first doped region of the first dopant type in the well region, and a second doped region of a second dopant type disposed in the well region and over the first doped region. The second doped region comprises first recesses exposed through a surface of the second doped region, and a first portion of the second doped region on the surface comprises a first doping concentration of the second dopant type greater than a second doping concentration of a second portion of the second doped region away from the first recesses.