High-speed InAlAs digital alloy avalanche photodiode

作者：W. Wang, Jinshan Yao, Linze Li, Huachen Ge, Luyu Wang, Liqi Zhu, Qiushi Chen, Hong Lü, Baile Chen · 发表于：Applied Physics Letters · 年份：2023 · DOI：10.1063/5.0169935 · 被引用次数：14 · 研究领域：Advanced Optical Sensing Technologies、Semiconductor Quantum Structures and Devices、Advanced Semiconductor Detectors and Materials

Digital alloy (DA) InAlAs on the InP substrate exhibits a lower excess noise compared to a traditional In0.52Al0.48As random alloy as the multiplication layer in avalanche photodiodes (APDs). This work implements DA InAlAs as the multiplication layer in a 1550 nm separate absorption, grading, charge, and multiplication APD and characterizes the performances through various analyses. The device reaches a maximum gain of 221 before avalanche breakdown, with a maximum gain-bandwidth product of more than 140 GHz. At 90% breakdown voltage, the dark current density is 4.1 mA/cm2, and the responsivity is 0.48 A/W at unit gain. Excess noise factors were identified, yielding an effective k value of around 0.15, which is lower than that of random alloy In0.52Al0.48As APDs (k ∼0.2). These findings show that DA InAlAs has the potential to be a promising material for high-performance APDs.