Schottky barrier parameters and structural properties of rapidly annealed Zr Schottky electrode on p-type GaN

The Schottky barrier junction parameters and structural properties of Zr/p-GaN Schottky diode are explored at various annealing temperatures.Experimental analysis showed that the barrier height (BH) of the Zr/p-GaN Schottky diode increases with annealing at 400 ℃ (0.92 eV (Ⅰ-V)/1.09 eV (C-V)) compared to the asdeposited one (0.83 eV (Ⅰ-V)/0.93 eV (C-V)).However,the BH decreases after annealing at 500 ℃.Also,at different annealing temperatures,the series resistance and BH are assessed by Cheung's functions and their values compared.Further,the interface state density (Nss) of the diode decreases after annealing at 400 ℃ and then somewhat rises upon annealing at 500 ℃.Analysis reveals that the maximum BH is obtained at 400 ℃,and thus the optimum annealing temperature is 400 ℃ for the diode.The XPS and XRD analysis revealed that the increase in BH may be attributed to the creation of Zr-N phases with increasing annealing up to 400 ℃.The BH reduces for the diode annealed at 500 ℃,which may be due to the formation of Ga-Zr phases at the junction.The AFM measurements reveal that the overall surface roughness of the Zr film is quite smooth during rapid annealing process.