Crosstalk analysis for mesa-based in-device passivated InGaAs photodetectors

Electrical crosstalk of in-device passivated mesa-based InGaAs photodetectors has been analyzed by a three-pixel mini array illuminated from the backside. In-device passivation of mesa-based lattice-matched InGaAs photodetectors significantly suppresses the surface-related component of dark current—however, inter-pixel crosstalk increases due to the depletion condition of the in-device passivation layer between the pixels. The inter-pixel crosstalk originates mainly from the high electric field in the in-device passivation layer. Here, in mesa-based in-device passivated InGaAs photodetectors, inter-pixel crosstalk has been significantly improved by adjusting the electric field distribution between the pixels with the inclusion of a thin n-InP crosstalk-block layer without affecting the primary purpose of the detector structure, which is strong resistivity to surface-related dark current increase.