N-polar GaN以其特有的材料特性和化学活性日益受到研究者关注,而N-polar GaN上欧姆接触也成为研究的热点.以Ti/Al/Ni/Au作为欧姆接触金属,分析了N-polar GaN上欧姆接触的最优退火条件,并借助剖面透射电子显微镜(TEM)和能量色散X射线能谱仪(EDX)研究了金属和N-polar GaN之间的反应生成物.结果表明,当退火温度升高到860℃时,可得到比接触电阻率ρc为1.7×10-5Ω·cm2的最优欧姆接触特性.TEM和EDX测试发现,除了生成已报道的AlN,还会在界面处产生多晶AlOx,两者共同作用会进一步拉高势垒,从而对N-polar GaN上欧姆接触产生不利影响.%N-polar GaN and ohmic contact on it have received more attentions for its unique material properties and chemical activity.Using Ti/Al/Ni/Au as ohmic contact metals,optimal annealing conditions and interracial reactions between metals and Npolar GaN were studied by cross-section transmission electron microscopy (TEM) and energy dispersive X ray energy spectrometer (EDX).Results showed that when the annealing temperature was increased to 860 ℃,the optimal specific contact resistivity ρc was 1.7 × 10-5 Ω · cm2.TEM and EDX analyses showed that,in addition to reported AlN,polycrystalline AlOx were founded at the interface.They both increase the height of potential barrier and result in adverse effects on ohmic contact on N-polar GaN.
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