Surface chemical states, electrical and carrier transport properties of Au/ZrO2/n-GaN MIS junction with a high-k ZrO2 as an insulating layer

Abstract High-k zirconium oxide (ZrO 2 ) thin insulating layer is deposited on n-type GaN and explored its chemical properties by XPS technique. XPS core level spectra confirms that the formation of ZrO 2 thin film on the n-GaN substrate. Later, the Au/ZrO 2 /n-GaN MIS junction is constructed with a ZrO 2 as insulating layer and correlated its electrical properties with the Au/n-GaN MS junction. Results present that a high barrier height (0.94 eV) is obtained for the MIS junction compared with the MS junction (0.73 eV), suggesting the barrier height is altered by the ZrO 2 insulating layer. The estimated interface state density (N SS ) of the MIS junction is lower compared with the MS junction, revealing that the high-k ZrO 2 thin insulating layer decreased N SS . Results confirmed that the reverse leakage current mechanism is governed by a Poole-Frenkel emission in both MS and MIS junctions.