Dependance of avalanche photodiode characteristics on active area geometry

The work presents an analysis of avalanche photodiode (APD) with spherical p-n junction. The calculation results are given for the dependence of the avalanche multiplication and noise parameters on geometry and on the incident light wavelength. As an example we modeled one structure for Si-APD and one structure for InGaAs/InP-APD. The novel structure has lower or comparable noise factors in comparison with the best of the reach-through APDs and earlier works of these authors on the spherical contact surface APDs. InGaAs/InP-APD are modeled to show the possibility of using the spherical p-n junction for that type of APD.