Microstructural and chemical properties of high-k holmium oxide (Ho2O3) and its effect on interface properties and current transport process of Au/n-GaN/Ti/Al Schottky contact as an interlayer

To comprehend the effect of the e-beam deposited high-k holmium oxide (Ho₂O₃) on the electrical possessions of Au/n-GaN/Ti/Al Schottky contact (SC), Au/Ho₂O₃/n-GaN/Ti/Al MIS-type contact was created with a Ho₂O₃ interlayer. The microstructural and chemical possessions of Ho₂O₃ film were assessed using XRD, XPS, TEM and EDX approaches. XRD, XPS, TEM and EDX studies indicate that the Ho₂O₃ layer exists on the GaN. The electrical features of the SC and MIS contact were probed using I-V and C-V approaches. The MIS contact shows a notable rectifying manner with a lower reverse leakage current than the SC. The MIS contact exhibits superior Φ_b (0.85 eV) than the SC (0.72 eV), indicating the Ho₂O₃ interlayer greatly rehabilitated the Φ_b of the SC. Using I-V, C-V, Cheung's and Norde processes, Φ_b, n, and R_S of the SC and MIS contacts were estimated, and the estimated Φ_b were well matched with each other, which signifying the techniques used here steadiness and validity. The MIS contact exhibits a lower magnitude of N_SS compared to the SC, portentous that the presence of the Ho₂O₃ layer played a significant part in diminishing N_SS. The log (I) versus log (V) of forward bias of the SC and MIS contact reveals the ohmic nature and space charge limited current (SCLC) at the lower bias and upper bias sections. The conclusions suggest that the Ho₂O₃ material has potential for building MIS/MOS devices.