Modeling of avalanche gain for high-speed InP/InGaAs avalanche photodiodes

InP/InGaAs avalanche photodiodes (APDs) have been widely used for high-speed optical receivers because of their advantages of high avalanche gain and high sensitivity. Generally, avalanche photodiodes are operated at near the breakdown voltage to improve gain characteristic. However, process variations of APD can cause the fluctuations of characteristics, such as avalanche gain, breakdown voltage, and dark current, which degrade proper operating characteristics of APDs. In this paper, the characteristic variations of InP/InGaAs avalanche photodiodes are investigated using commercial TCAD tool.