AlN成核层对近紫外LED外延生长的影响  

Effect of AlN Nucleation Layer on the Epitaxial Growth of Near-Ultraviolet LED

作　　者：李婷婷 周玉春 杨路华 李晓波 王静辉 Li Tingting;Zhou Yuchun;Yang Luhua;Li Xiaobo;Wang Jinghui(Tong Hui Electronics Technologies Co.,Ltd.,Shifiazhuang 050051,China;The Inner Mongolia Autonomous Region Electronic Information Products Quality Inspection Institute,Hohhot 010010,China;Xi＇an Zoom View Optoelectronics Science ＆ Technology Co.,Ltd.,Xi＇an 710065,China)

机构地区：[1]同辉电子科技股份有限公司,石家庄050051 [2]内蒙古自治区电子信息产品质量检验院,呼和浩特010010 [3]西安中为光电科技有限公司,西安710065

出　　处：《半导体技术》2018年第9期684-688,696,共6页Semiconductor Technology

基　　金：河北省创新能力提升计划项目(18960607H)

摘　　要：在图形化蓝宝石衬底上制备了InGaN/AlGaN近紫外发光二极管（LED）。采用金属有机化学气相沉积（MOCVD）方法外延生长了不同厚度的AlN成核层,系统研究了AlN成核层厚度对外延层质量和InGaN/AlGaN近紫外LED（波长395 nm）光电性能的影响。使用透射电子显微镜对外延层的截面结构及位错进行表征。结果表明,随着AlN成核层厚度的增加,位错密度不断减小,且量子阱表面V形坑尺寸逐渐减小。LED器件的光学性能和电学性能随着V形坑尺寸的减小而提高,归一化外量子效率最大值由0.55增至1;在电流350 m A时,正向电压从3.54 V降至3.45 V,又升高至3.60 V。当AlN成核层厚度超过临界值后,位错密度不降反升,量子阱表面的V形坑密度增加,导致量子阱的有效发光面积减小,外延层质量下降。InGaN/AlGaN近紫外LED的光电性能与AlN成核层厚度密切相关,最佳AlN成核层厚度为50.22 nm。InGaN/AlGaN near-ultraviolet（ UV） light-emitting diodes（ LEDs） were grown on patterned sapphire substrate. The AlN nucleation layers of different thicknesses were grown by the metal organic chemical vapor deposition（ MOCVD） method. The effects of the thickness of AlN nucleation layer on the quality of the epitaxial layer and the photoelectric properties of InGaN/AlGaN near-UV LEDs（ with a wavelength of 395 nm） were investigated systematically. The cross-section structure and dislocation of the epitaxial layer were characterized by the transmission electron microscope. The results show that the dislocation density and the size of the V-shaped pit on the quantum well surface decrease with the increase of AlN nucleation layer thickness. The optical and electrical properties of LED devices are improved with the decrease of the V-shaped pit size,and the maximum value of the normalized external quantum efficiency increases from 0. 55 to 1. The forward voltage at 350 m A drops from 3. 54 V to 3. 45 V initially,and then rises to 3. 60 V. When the thickness of the AlN nucleation layer exceeds the critical value,the dislocation density and the V-shaped pit density on the quantum well surface increase,whichleads to a decrease of the effective luminescence area and a decrease in the quality of the epitaxial layer.The photoelectric properties of InGaN/AlGaN near-UV LEDs are closely related to the AlN nucleation layer thickness,and the best AlN nucleation layer thickness is 50. 22 nm.

关 键 词：AlN成核层 近紫外LED 蓝宝石图形衬底(PSS) 腐蚀坑密度 外量子效率 

分 类 号：TN304.054[电子电信—物理电子学] TN312.8