级联倍增InAlAs/InAlGaAs雪崩光电二极管暗电流成分分析

Analysis of Dark Current Components of InAlAs/InAlGaAs Cascade Multiplication Avalanche Photodiode

摘要:

实验制备了级联倍增InAlAs/InAlGaAs雪崩光电二极管,对二极管暗电流随台面直径和温度的变化进行了研究分析。结合暗电流函数模型,利用Matlab软件对暗电流的各成分进行了数值计算,并仿真研究了芯片结构的缺陷浓度N_t和表面复合速率S对暗电流的影响。结果表明,二极管暗电流主要来自于体暗电流,而非表面漏电流。在工作点偏压90V处,受缺陷影响的缺陷辅助隧穿电流I_tat在暗电流中占据了主导,并推算出了芯片结构的缺陷浓度N_t约为10¹⁹m-3、吸收区中的缺陷浓度NInGaAs约为7×10¹⁵m-3。由于芯片结构的缺陷主要来源于InAlAs/InAlGaAs倍增区和InGaAs吸收区,而吸收区缺陷占比很少,因此认为缺陷主要来自于异质结InAlAs/InAlGaAs倍增区。

Abstract:

InAlAs/InAlGaAs cascade multiplication avalanche photodiode was fabricated experimentally. The dark current of the diode was studied and analyzed with the change of the diameter and temperature of the mesa. The components of the dark current were calculated by MATLAB combined with the dark current function model. The effects of defect concentration N_t and surface recombination rate Sof the chip structure on the dark current were simulated and studied. The results show that the dark current of the diode mainly comes from the body dark current, not from the surface leakage current. The defect-assisted tunneling current I_tat affected by defect concentration dominates the dark current at 90V bias. The defect concentration in the chip structure N_t is 10¹⁹m-3 and the defect concentration in the absorption region NInGaAs is 7×10¹⁵m-3. Because the defects mainly come from the InAlAs/InAlGaAs multiplication region and the absorption region, and the proportion of the defects in the absorption region is very small, so it believes that the defects mainly come from the heterojunction InAlAs/InAlGaAs multiplication region.