氧化Au/Ni/p-GaN欧姆接触形成的机理  

Investigation on Mechanism of Oxidized Au/Ni/p-GaN Ohmic Contact

作　　者：胡成余[1] 秦志新[1] 冯振兴[2] 陈志忠[1] 杨华[1] 杨志坚[1] 于彤军[1] 胡晓东[1] 姚淑德[2] 张国义[1] 

机构地区：[1]北京大学物理学院 [2]北京大学物理学院技术物理系,北京100871

出　　处：《Journal of Semiconductors》2005年第6期1154-1158,共5页半导体学报（英文版）

基　　金：国家高技术研究发展计划(批准号:8632001AA313110;2001AA313060和2001AA313140);北京市科技项目(批准号:H030430020230);国家自然科学基金(批准号:60276010;60276034;60406007;60476028)资助项目~~

摘　　要：用卢瑟福背散射(RBS)和同步辐射X射线衍射(XRD)研究了p-GaN上的Ni/Au电极在空气下不同温度合金后的微结构的演化,并揭示这种接触结构的欧姆接触形成机制.研究不同温度下比接触电阻(ρc)的变化,发现从450℃开始Au扩散到GaN的表面在p-GaN上形成外延结构以及O向电极内部扩散反应生成NiO对降低ρc起到了关键的作用.在500℃时,Au的外延结构进一步改善,O进一步向样品内部扩散生成NiO,ρc也达到了最低值.但当合金温度升高到600℃时,金属半导体界面NiO的大部分或全部向外扩散,从而脱离与pGaN的接触,使ρc显著升高.By synchrotron X-ray diffraction (XRD) and Rutherford back scattering(RBS),the microstructure evolution of oxidized Ni/Au contact to p-GaN annealed at different temperature in air are investigated.Considering a sharp decrease in the ρ c after 450℃-annealing,it is suggested that the epitaxial structures of Au on p-GaN and the formation of NiO play a critical role in forming low resistance Ohmic contact to p-GaN.At 500℃,the epitaxial structure of Au is improved further and the O also diffuses dipper into the samples.At the same time,the ρ c get the lowest value.At 600℃,the O begin to diffuse outwards,so it is implied that most or all of the NiO in the metal-semiconductor inerface begin to diffuse outwards at this temperature.Therefore,it shows that the degradation of Ohmic contact for oxidized Ni/Au is related to the full outdiffusion of the NiO in the metal-semiconductor interface,which causes NiO detached from p-GaN.

关 键 词：p型氮化镓 镍/金 比接触电阻 同步辐射 卢瑟福背散射 

分 类 号：TN304.2[电子电信—物理电子学]