【Member News】Professor Wang Gang's team of Sun Yat-sen University in Research progress of Ga₂O₃ heterojunctions in the field of power devices

Abstract

      Beta gallium oxide (β-Ga₂O₃) has attracted significant attention for applications in power electronics due to its ultra-wide bandgap of ~ 4.8 eV and the large critical electric field of 8 MV/cm. These properties yield a high Baliga’s figures of merit (BFOM) of more than 3000. Though β-Ga₂O₃ possesses superior material properties, the lack of p-type doping is the main obstacle that hinders the development of β-Ga₂O₃-based power devices for commercial use. Constructing heterojunctions by employing other p-type materials has been proven to be a feasible solution to this issue. Nickel oxide (NiO) is the most promising candidate due to its wide band gap of 3.6–4.0 eV. So far, remarkable progress has been made in NiO/β-Ga₂O₃ heterojunction power devices. This review aims to summarize recent advances in the construction, characterization, and device performance of the NiO/β-Ga₂O₃ heterojunction power devices. The crystallinity, band structure, and carrier transport property of the sputtered NiO/β-Ga₂O₃ heterojunctions are discussed. Various device architectures, including the NiO/β-Ga₂O₃ heterojunction pn diodes (HJDs), junction barrier Schottky (JBS) diodes, and junction field effect transistors (JFET), as well as the edge terminations and super-junctions based on the NiO/β-Ga₂O₃ heterojunction, are described.

      Recently, Associate Professor Lu Xing and Professor Wang Gang of Sun Yat-sen University summarized the research progress of NiO/β-Ga₂O₃ heterojunction in the field of power devices, and made prospects for its future development. The review unfolds from three aspects of the construction, characterization and device performance of NiO/β-Ga₂O₃ heterojunction, discusses the crystallization properties, band structure and carrier transport characteristics of NiO/β-Ga₂O₃ heterojunction prepared by sputtering method. The latest progress of various device structures are introducted, including NiO/β-Ga₂O₃ heteropn junction diode (HJD), junction barrier Schottky diode, junction field effect transistors and edge terminal structure and superjunction (SJ) structure based on NiO/β-Ga₂O₃ heterojunction. In addition, the summary and outlook are conducted on the key problems of NiO/β-Ga₂O₃ include material quality, device structure optimization, interfacial state, and device reliability.

      This review summarizes the development status of NiO/β-Ga₂O₃ heterojunction in the field of power devices, which provides a reference for the design of high-performance NiO/β-Ga₂O₃ heterojunction devices, and plays a positive role in the future development of β-Ga₂O₃ bipolar devices.

      The article is published in Journal of Semiconductors, titled “Recent advances in NiO/Ga₂O₃ heterojunctions for power electronics”.

Fig 1 NiO/ β- A milestone in the development of Ga₂O₃ heterojunction power devices.

Paper Link：http://www.jos.ac.cn/en/article/doi/10.1088/1674-4926/44/6/061802