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

Abstract

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 (NSS) value for the MIS diode is beneath the SD, suggesting that the Er2O3 layer significantly contributes to the reduction of NSS. 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.