Planar avalanche photodiode and producting method thereof

The present invention relates to a planar avalanche photodiode manufactured by a single etched ring structure and a single diffusion process, and a producing method thereof. In a planar avalanche photodiode where an InP buffer layer, an InGaAs light absorption layer, an InGaAsP grading layer, an InP electric field control layer, and an InP layer are formed, the InP layer has the each regions of a single wet or dry etched ring structure by using the etch mask layer of ring structures which are formed on the InP layer. Thereby, a simple manufacturing process, high reproducibility, low arm coefficient, and high photo detection efficiency can be obtained.