p-IrO<sub>x</sub>/n-β-Ga<sub>2</sub>O<sub>3</sub> Heterojunction Diodes With 1-kV Breakdown and Ultralow Leakage Current Below 0.1 μA/cm<sup>2</sup>
Ruitao Zheng, Wenyong Feng, Chao Liao, Huichao Hu, Xing Lü, Jun Liang, Zimin Chen, Gang Wang, Yanli Pei
Abstract
A p-type IrOx was first applied to <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$\beta $ </tex-math></inline-formula> -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 <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$10^{{21}}$ </tex-math></inline-formula> /cm3. Ir <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$^{{3}+}$ </tex-math></inline-formula> 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 <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$\beta $ </tex-math></inline-formula> -Ga2O3 epitaxial layer without optimized electric field management techniques. A high breakdown voltage ( <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">${V} _{B}$ </tex-math></inline-formula> ) of 1005 V and a relatively low specific ON-resistance ( <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">${R} _{{ \text {ON, sp}}}$ </tex-math></inline-formula> ) of 4 <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$\text{m}\Omega \cdot $ </tex-math></inline-formula> cm2 were achieved. In particular, the reverse leakage current density remained below <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$0.1 ~\mu \text{A}$ </tex-math></inline-formula> /cm2 before breakdown. The results provide a new way to develop high-quality <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$\beta $ </tex-math></inline-formula> -Ga2O3 p-n heterojunction.