Exploration of microstructural, chemical states and electrical features of the Au/Er₂O₃/n-GaN MIS diode with a Er₂O₃ interlayer

The study involved the formation of high-k erbium oxide (Er₂O₃) films on the n-GaN surface and evaluated their microstructural and chemical states by XRD, TEM and XPS approaches. By employing Er₂O₃ as an interlayer between the Au and n-GaN substrate, the metal/insulator/ semiconductor (MIS) diode is developed and explored its electrical features by I–V and C–V procedures. The electrical properties of the MIS diode demonstrate a better rectification nature with a lower leakage current compared with the Au/n-GaN Schottky diode (SD). The MIS diode's derived barrier height (BH) is higher than the SD, suggesting that Er₂O₃ plays a momentous role in altering the BH. The BH was determined using Cheung's and Norde techniques, and the measurements showed a high degree of consistency, indicating the methods used are valid. The derived density of states (N_SS) value for the MIS diode is beneath the SD, suggesting that the Er₂O₃ layer significantly contributes to the reduction of N_SS. Under reverse bias, the PFE is a dominant current mechanism in the lower-bias, whereas the SE is the leading current mechanism in the higher-bias region of the SD. However, the PFE is the prevailing conduction mechanism in the lower-bias and higher-bias regions of the MIS diode. Outcomes of the investigation reveal that the Er₂O₃ thin films are favorable interfacial layers for fabricating MIS/MOS diodes.