Mesa-structured AlGaAsSb APD: dark current and noise analysis

作者：Yuhang He, Rui Wang, Yan Liang, Yingqiang Xu, Guo Wei Wang, Haiqiao Ni, Shuo Wang, Zhichuan Niu, Xiaohong Yang · 发表于：Journal of Semiconductors · 年份：2025 · DOI：10.1088/1674-4926/25020025 · 被引用次数：3 · 研究领域：Advanced Semiconductor Detectors and Materials、Semiconductor Quantum Structures and Devices、Advanced Optical Sensing Technologies

Abstract Avalanche photodiode (APD) is a kind of photodetector with important applications in optical communication, light detection and ranging (LIDAR) and other fields. APDs fabricated using the recently developed AlGaAsSb as the multiplication material exhibit excellent noise performance. In this work, we report a low-noise separate absorption, grading, charge, and multiplication (SAGCM) InGaAs/AlGaAsSb APD operating at 1550 nm. A double-mesa structure was fabricated to reduce the dark current. Numerical simulations were conducted to compare two different mesa-structured APDs. By analyzing the electric field distribution, it was found that the electric field at the edge of the multiplication region in the double-mesa APD is nearly 100 kV/cm lower than that of the single-mesa structure. Experimental results demonstrate that after device punch-through, the double-mesa APD’s dark current can be reduced by up to four times compared to the single-mesa APD. Quantitative analysis of the dark current components in the AlGaAsSb APD further confirms that the low sidewall electric field in the double-mesa structure effectively suppresses the trap-assisted tunneling. Additionally, noise measurements indicate a k -value of approximately 0.014, which is significantly lower than that of traditional multiplication materials. This work provides preliminary validation for further performance improvements in low noise and low dark current AlGaAsSb APDs.