Effects of thermal annealing on the electrical and structural properties of Mo/Au schottky contacts on n-GaN
2020; Elsevier BV; Volume: 853; Linguagem: Inglês
10.1016/j.jallcom.2020.156978
ISSN1873-4669
AutoresJiabo Chen, Zhaoke Bian, Zhihong liu, Dan Zhu, Xiaoling Duan, Yinhe Wu, Yanqing Jia, Jing Ning, Jincheng Zhang, Yue Hao,
Tópico(s)GaN-based semiconductor devices and materials
ResumoThe current conduction mechanisms of the Mo/Au Schottky contacts on n-GaN with post metal annealing at 300, 500 and 700 °C have been investigated. The barrier height φB and ideality factor n directly extracted from the measured current-voltage characteristics based on the thermionic emission (TE) theory show variations with the temperature, suggesting that inhomogeneous barrier heights were formed. A modified TE model considering the barrier height inhomogeneity with a Gaussian distribution was found to be able to explain the measurement data well. From the modified Richardson plot, the mean barrier heights φB¯ = 0.598, 0.566, 0.789, 0.567 eV and the standard deviations σ0 = 125.70, 113.14, 89.77, 121.24meV were obtained for the sample with as-deposited Mo/Au, the one with post metal annealing at 300 °C, the one annealed 500 °C and the one annealed at 700 °C, respectively. The specific on-resistance doesnot show any obvious change after post thermal annealing. The best values of reverse leakage current and the breakdown voltage were achieved after post metal annealing at 500 °C. Transmission Electron Microscopy (TEM) images and energy dispersive X-ray (EDX) spectroscopy mapping results reveal that the interaction between Mo and GaN during the annealing contributes to the observed Schottky barrier height difference under different annealing conditions.
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