Utilization of InGaAsP charge layer in InGaAs/InP SACM APD

We report on the design, simulation, fabrication and characterization of an InGaAsllnP avalanche photodiode (APD). The investigated InGaAs/lnP APD structure for lightwave transmission systems consists of separate absorption, charge and multiplication layers (SACM). We demonstrate two types of charge layer - sectional InGaAsP/lnP and simple InGaAsP grown by metalorganic chemical vapour deposition (MOCVD). The band diagram, electrical field distribution and current-voltage (I-V) characteristics have been simulated. The prepared photodiodes show breakdown voltage near 35 V without a guard-ring, responsivity 0.85 A/TV at 20 V@131O nm and avalanche gain up to 4.