An avalanche photodiode (APD) has a first semiconductor substrate having a first doping type. A first semiconductor layer is on top of the first semiconductor substrate. The first semiconductor layer is doped with the first doping type. A second epitaxial layer is on top of the first semiconductor layer. The second epitaxial layer is in-situ doped with the first doping type at a concentration higher than a concentration of the first doping type in the first semiconductor layer. A third epitaxial layer is on top of the second epitaxial layer. The third epitaxial layer is in-situ doped with a second doping type. The doping of the third epitaxial region forms a first p-n junction with the doping of the second epitaxial layer, wherein a carrier multiplication region includes the first p-n junction, and wherein the third epitaxial layer forms an absorption region for photons. A first implanted region is within the third epitaxial layer. The implanted region is doped with the second doping type.