垂直腔面发射半导体激光器氧化优化研究  

Optimization of Oxidation for Vertical Cavity Surface Emitting Semiconductor Lasers

作　　者：陈中标 崔碧峰 郑翔瑞 杨春鹏 闫博昭 王晴 高欣雨 Chen Zhongbiao;Cui Bifeng;Zheng Xiangrui;Yang Chunpeng;Yan Bozhao;Wang Qing;Gao Xinyu(Key Laboratory of Opto-Electronics Technology of Ministry of Education,Faculty of Information Technology,Beijing University of Technology,Beijing100124,China)

机构地区：[1]北京工业大学信息学部光电子技术教育部重点实验室,北京100124

出　　处：《中国激光》2024年第8期16-22,共7页Chinese Journal of Lasers

基　　金：国家自然科学基金(60908012,61575008,61775007);北京市自然科学基金(4172011)。

摘　　要：GaAs基垂直腔面发射激光器在干法刻蚀过程中,台面侧壁形成的缺陷会导致器件出现层结构分层、断裂以及氧化孔不规则等问题。针对该问题,提出了一种干法刻蚀与硫化铵钝化相结合的氧化前预处理方案,研究了硫化铵钝化处理对器件层结构以及氧化工艺稳定性的影响。扫描电子显微镜测试结果表明:器件侧壁层结构的分层现象减少,器件结构稳定性更好;高Al层的氧化速率更稳定,氧化孔形状更为规则。将该工艺方案用于制备氧化孔直径为5μm的940 nm垂直腔面发射激光器,室温下,与传统工艺制备的器件相比,钝化后的器件的斜率效率提高了5%,各器件之间的性能一致性更好。同时,在1 mA的驱动电流下,激光器的边模抑制比可达36 dB,处于单模激射状态。在优化后的氧化工艺条件下,制备了形状规范的氧化孔结构,进一步改善了氧化限制型垂直腔面发射激光器的性能。Objective Vertical cavity surface-emitting lasers(VCSELs)have advantages such as a single longitudinal mode,a low threshold,and ease of two-dimensional integration.VCSELs have been widely used in data transmission,optical communication,and threedimensional sensing.Oxidation is the most common process for oxide-confined VCSELs.AlGaAs materials with high Al contents are oxidized via wet oxidation to form oxide apertures of aluminum oxide,and the structures of oxide apertures with different shapes and sizes have different effects on the optoelectronic characteristics of VCSELs.However,during the actual oxidation of the AlGaAs oxide confinement layer,the shape and size of the oxide aperture do not satisfy expectations because of various factors,which adversely affect the performance of the device in terms of the excitation mode,threshold current,and divergence angle.In this study,the dry etching and wet oxidation processes of VCSELs are experimentally investigated,and an optimized process scheme for oxidation pretreatment that combines dry etching and(NH4)2S passivation is developed.An(NH4)2S solution is used to passivate the table structure after dry etching,which achieves a stable oxidation rate and improves the quality of the oxide aperture shapes,further improving the optoelectronic characteristics of VCSELs and extending the applications of VCSELs in optoelectronics.Methods In this study,an(NH4)2S solution is used.Prior to oxidation,a cleaned VCSEL is passivated in a(NH4)2S(sulfur mass fraction>8%)solution in a heated water bath.After oxidation,the surface and sidewall microstructures of the VCSEL are observed using scanning electron microscopy(SEM).The shapes and sizes of the oxidation apertures of the VCSELs are observed separately using a microscope,and the oxidation rates of the oxidation apertures are determined.Based on this,the photoelectric properties of the unpassivated and passivated VCSELs are comparatively analyzed.Results and Discussions After wet oxidation,the layered structure of the unpassivated

关 键 词：激光器 垂直腔面发射激光器 氧化孔 湿法氧化 钝化 干法刻蚀 

分 类 号：TN248.4[电子电信—物理电子学]