1School of Physics, Dalian University of Technology, Dalian 116024 2Engineering Research Center of Nuclear Technology Application (Ministry of Education), East China Institute of Technology, Nanchang 330013 3Jiangxi Province Engineering Research Center of New Energy Technology and Equipment (Ministry of Education), East China Institute of Technology, Nanchang 330013 4School of Microelectronics, Dalian University of Technology, Dalian 116024 5State Key Laboratory on Integrated Optoelectronics, School of Electronic Science and Engineering, Jilin University, Changchun 130012
Abstract：For the frequency range of 1 kHz–10 MHz, the interface state density of Ni contacts on p-GaN is studied using capacitance-voltage ($C$–$V$) and conductance-frequency-voltage ($G$–$f$–$V$) measurements at room temperature. To obtain the real capacitance and interface state density of the Ni/p-GaN structures, the effects of the series resistance ($R_{\rm s}$) on high-frequency (5 MHz) capacitance values measured at a reverse and a forward bias are investigated. The mean interface state densities obtained from the $C_{\rm HF}$–$C_{\rm LF}$ capacitance and the conductance method are $2\times10^{12}$ eV$^{-1}$cm$^{-2}$ and $0.94\times10^{12}$ eV$^{-1}$cm$^{-2}$, respectively. Furthermore, the interface state density derived from the conductance method is higher than that reported from the Ni/n-GaN in the literature, which is ascribed to a poor crystal quality and to a large defect density of the Mg-doped p-GaN.
2017, Vol. 34 
