Methods for forming a buried p-n junction and avalanche photodiodes incorporating same are disclosed. The method includes forming a well in a semiconductor layer, wherein a depth of the well is selected as a function of the desired shape of the p-n junction in the edge region of the avalanche photodiode. A diffusion mask is then formed on the semiconductor layer, wherein the diffusion mask includes at least two openings per APD formed, wherein one opening is a diffusion window and the other is a diffusion sink. The depth of the p-n junction in the active region of the APD is based, in part, on an attribute of the diffusion mask relating to the diffusion sink.