8 × 8 format InGaAs/InP avalanche photodiode plane array for 3D　imaging laser radar system

摘要

This paper reports a planar structure InGaAs/InP avalanche photodetector focal plane arrays. Their material structure useseparate absorption, grading, charge and multiplication layer. The pixel pitch of 8 × 8 format detectors is 250 μm.The breakdown voltage (VBD) is typically in the range of 65 to 70 V for most of the devices on the same wafer. Thetypical dark current at 90% of VBD is 3 nA, dark currents as low as 0.5 nA at 90% of VBD have also been observed forsome diodes, corresponding to a dark current density of 1 × 10~(-5) A/cm~2. The photocurrent starts to increase at the“punch-through” voltage V_p of 43 V. The responsivity at 1.55 μm is 0.91 A/W at unity gain and the multiplication layeris estimated to be 1.2 μm. Each device on the same wafer has excellent characteristics and high uniformity throughmeasurement, laying a solid foundation for 3D imaging laser radar systems.