Research on the correlation between the dual diffusion behavior of zinc in InGaAs/InP single-photon avalanche photodiodes and device performance

InGaAs/InP单光子雪崩光电二极管中锌的双扩散行为与器件性能关联性研究

The development of InGaAs/InP single-photon avalanche photodiodes(SPADs)necessitates the utiliza-tion of a two-element diffusion technique to achieve accurate manipulation of the multiplication width and the dis-tribution of its electric field.Regarding the issue of accurately predicting the depth of diffusion in InGaAs/InP SPAD,simulation analysis and device development were carried out,focusing on the dual diffusion behavior of zinc atoms.A formula of X_(j)=k√t-t_(0)+c to quantitatively predict the diffusion depth is obtained by fitting the simulated twice-diffusion depths based on a two-dimensional(2D)model.The 2D impurity morphologies and the one-dimensional impurity profiles for the dual-diffused region are characterized by using scanning electron micros-copy and secondary ion mass spectrometry as a function of the diffusion depth,respectively.InGaAs/InP SPAD devices with different dual-diffusion conditions are also fabricated,which show breakdown behaviors well consis-tent with the simulated results under the same junction geometries.The dark count rate(DCR)of the device de-creased as the multiplication width increased,as indicated by the results.DCRs of 2×10^(6),1×10^(5),4×10^(4),and 2×10^(4) were achieved at temperatures of 300 K,273 K,263 K,and 253 K,respectively,with a bias voltage of 3 V,when the multiplication width was 1.5µm.These results demonstrate an effective prediction route for accu-rately controlling the dual-diffused zinc junction geometry in InP-based planar device processing.

InGaAs/InP单光子雪崩二极管(SPAD)研制需要采用两次元素扩散方法,以实现对倍增层厚度以及其电场分布的精确控制。针对两次扩散深度的有效预测问题,围绕InGaAs/InP SPAD中锌原子的两次扩散行为开展了仿真分析和器件研制。基于二维模型拟合模拟的两次扩散深度,建立了预测扩散深度的公式X_(j)=k√t-t_(0)+c。利用扫描电子显微镜和二次离子质谱表征器件双扩散区的二维杂质形态和一维杂质分布。制备了不同扩散组合多种倍增层厚度的InGaAs/InP SPAD器件,各倍增层厚度与实测击穿电压呈现线性关系,击穿电压与仿真结果具有良好的一致性。根据器件暗计数率(DCR)结果,提高倍增层厚度减小了器件DCR。在倍增层厚度为1.5µm时,过偏压3 V下温度为300 K、273 K、263 K、253 K时分别具有2×10^(6)、1×10^(5)、4×10^(4)、2×10^(4)的DCR。这些结果证明在基于InP的平面器件处理中精确控制双扩散锌结几何形状的有效预测路线。