N掺杂ZnO薄膜的接触特性  

The Ni/Au Contacts to N-doped ZnO

作　　者：单正平[1] 顾书林[1] 朱顺明[1] 刘伟[1] 刘少波[1] 刘雪冬[1] 汤琨[1] 张荣[1] 郑有炓[1] 

机构地区：[1]南京大学物理系江苏省光电信息功能材料重点实验室,江苏南京210093

出　　处：《发光学报》2008年第3期503-507,共5页Chinese Journal of Luminescence

基　　金：国家重点基础研究规划(2006CB921803);中国高科技发展研究项目(2007AA03Z404);国家自然科学基金(60776013;60576017;50532100)资助项目

摘　　要：氧化锌(ZnO)是一种直接带隙半导体材料,室温下带隙为3.37eV,激子束缚能为60meV。ZnO因其优越的光电特性在高亮度蓝紫光发光器件、紫外探测器件和短波长激子型激光器等方面具有广阔的应用前景。而要实现大功率的光电器件,稳定可靠的欧姆接触是必需的。研究了氮气氛条件下,不同温度快速退火对氮掺杂ZnO样品的电学性质以及Ni/Au与其接触特性的影响。原生样品表现为弱的肖特基接触,适当温度退火后,由肖特基转成了欧姆接触,650℃退火后得到最小比接触电阻率8×10-4Ω·cm2。霍尔测量表明550℃快速退火后,样品的导电类型由p型转变成了n型。采用AES和GXRD分别研究了不同退火温度下Au、Ni、Zn、O的深度分布变化及退火后所生成的合金相。实验结果表明,退火所导致的薄膜电学性质的变化以及界面态和表面态的增加是接触特性变化的原因。Zinc oxide （ZnO） is a strong candidate for logical importance for the fabrication of optoelectronic replacing GaN semiconductors that are of great techno-devices, because of its unique electrical and optical properties, namely, its large bandgap of 3.37 eV, low power threshold for optical pumping at room tempera-ture, and highly efficient UV emission resulting from a large exciton binding energy of 60 meV at room tempe-rature, and an easy wet etching process. For the realization of high performance ZnO-based optoelectronic devices, the achievement of high quality ohmic contacts is essential. So far, the metal schemes for ohmic contact to n-type zno mainly focus on A1 base and Ti base, such as,A1, A1/Pt, Ti/Au, Ti/A1/Pt/Au, and nonalloyed In. Pt-Ga via rapid annealing process, low specific contact resistance scope from 10^-4—10^-8Ω·cm^2 was obtained. For p-type ZnO, due to its difficulty in doping, contact to p-type ZnO has not been extensive studied. There＇s only a few report on Ni/Au, Au, Au/Ni/Au and Ni/ITO contact to Sb doped, P doped and ZnMgO p-type ZnO. Replacing O site by N is considered as a effective route to realize p-type ZnO. In this paper, we studied rapid annealing effect on the electric character of the N-doped ZnO film and effect on Ni/Au contacts to the N-doped ZnO film. A conversion from rectifying to ohmic behavior is observed for Ni/Au contacts to N-doped ZnO film. The as-deposited Ni/Au contacts to the as grown ZnO film shows nonlinear rectifying behavior, linear ohmic behavior appeared after rapid annealing at temperature up to 350℃. A minimum specific contact resistance of 8×10^-4 ·cm^2 was obtained after annealing at 650℃. Higher annealing temperatures degrade the ohmic contact behavior. Hall measurement suggests that the conductive type changed from p-type to n-type via rapid annealing process, which corresponds partly to the changed contact behavior. Analyses of the elements depth profile by Auger electron spectroscopy and glancing angle X-ray diffraction identified the r

关 键 词：N掺杂ZnO NI/AU 快速退火 欧姆接触 

分 类 号：O482.31[理学—固体物理]