p-IrOx/n-β-Ga₂O₃ Heterojunction Diodes With 1-kV Breakdown and Ultralow Leakage Current Below 0.1 μA/cm²

A p-type IrOx was first applied to <tex-math notation="LaTeX">β </tex-math> -Ga2O3 p-n heterojunction diodes (HJDs) in this work. It was fabricated by oxygen ion beam-assisted deposition (IBAD) method with a hole concentration of <tex-math notation="LaTeX">10^21 </tex-math> /cm3. Ir <tex-math notation="LaTeX">^3+ </tex-math> is the main valence state confirmed by X-ray photoelectron spectroscopy (XPS). The bandgap of 2.9 eV was determined by the transmittance spectrum, which is consistent with the HSE06 calculated band structure of Ir2O3. p-n HJDs were realized by deposition p-type IrOx layer on a lightly doped n-type <tex-math notation="LaTeX">β </tex-math> -Ga2O3 epitaxial layer without optimized electric field management techniques. A high breakdown voltage ( <tex-math notation="LaTeX">V B </tex-math> ) of 1005 V and a relatively low specific ON-resistance ( <tex-math notation="LaTeX">R _ ON, sp </tex-math> ) of 4 <tex-math notation="LaTeX">mΩ · </tex-math> cm2 were achieved. In particular, the reverse leakage current density remained below <tex-math notation="LaTeX">0.1 ~μ A </tex-math> /cm2 before breakdown. The results provide a new way to develop high-quality <tex-math notation="LaTeX">β </tex-math> -Ga2O3 p-n heterojunction.