祁昌亚,胡正飞,张燕,李向阳.二次退火对Au/Ni/Au/Ni/p-AlGaN欧姆接触组织结构的影响[J].光电子激光,2016,27(4):392~397 |
二次退火对Au/Ni/Au/Ni/p-AlGaN欧姆接触组织结构的影响 |
Effect of secondary annealing on the microstructure of Au/Ni/Au/Ni/p-AlGaN ohmi c contact |
投稿时间:2015-11-24 |
DOI: |
中文关键词: p-AlGaN 一次退火 二次退火 扩散 组织结构 |
英文关键词:p-AlGaN first annealing secondary annealing diffusion microstructure |
基金项目:中国科学院红外成像材料与器件重点实验室资助项目 (1.同济大学 材料科学与工程学院,上海 201804; 2.中国科学院上海技术物理研究所, 红外成像材料与器件重点实验室,上海 200083) |
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中文摘要: |
在蓝宝石衬底上,利用金属-有机物化学气相沉 积(MOCVD)方法制备p-i-n结构AlGaN基体,采 用常规工艺制作台面型紫外探测器。电子束蒸发蒸镀Ni/Au/Ni/Au(20nm/20 nm)结构制备 p 电极。经空气中550℃/3min一次退火和N2气氛中750℃/30s二次退火后得到欧姆接触。利用高分 辨透射电镜(HRTEM)和能谱(EDS)研究不同退火条件下p 电极接触的组织结构演变。结果 表明:一 次退火p电极金属层出现明显扩散,但仍维持初始的分层状态,金属/半导体接触界面产生 厚约4nm 的非晶层;二次退火后,金属电极分层现象和界面非晶层消失。金/半界面结构表现为半共 格关系,界面结 构有序性提高。Ni向外扩散,Au向内扩散,Ga扩散至金属电极,造成界面附近金属层富 集Au、Ga元素,导致p电极欧姆接触的形成。 |
英文摘要: |
AlGaN semiconductor with p-i-n structure was grown on sapphire subst rate using metal-organic chemical vapor deposition (MOCVD) system.Mesa-structure ultravio let detectors were fabricated by conventional technology.Ni/Au/Ni/Au (20nm/20nm/20nm/20nm) met al schemes were deposited by electron beam evaporation as p-type contact.After first annealing in air ambient at 550℃ for 3min and secondary annealing in N2ambient at 750℃ for 30s,an ohmic contact formed.Analysis on the microstructure evolution of the annealed p-electrode is carried out by high -resolution transmission electron microscopy (HRTEM) and energy dispersive spectrometer (EDS ).The results reveal that after first annealing,elements diffusion occurrs in p-electrode ,but metal schemes maintain the initial layers of the as-deposited sample.And a 4nm-thick amo rphous layer appears on the interface of metal and semiconductor.While after secondary annealing,the m etal schemes change sharply and the amorphous layer disappears.Microstructure a nalysis on the metal-semiconductor interface shows a semi-coherent relationship and enhanced orderliness.Ni outdi ffused to the surface of p-electrode,Au indiffused to the surface of GaN,and Ga diffused to metal elec trode,which results in the enrichment of Au and Ga near the interface.These phe nomena contribute to the formation of p-AlGaN ohmic contact. |
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