Vertical β-Ga2O3 Power Diodes: From Interface Engineering to Edge Termination

Ultra wide bandgap semiconductor beta-gallium oxide (beta-Ga2O3) has the potential in fabricating the next generation of power devices applied at high temperature and high voltage due to its superior material properties and cost competitiveness. However, the performance of the existing beta-Ga2O3 power diodes is far from the theoretical value because of the restriction of interface quality and edge electric field crowding effect. In this review, we introduce several effective interface engineering and edge termination techniques commonly used in vertical beta-Ga2O3 diodes, highlighting their design principles, key fabrication processes, physical mechanism, and merit/demerit. To realize the actual applications, the representative large-size beta-Ga2O3 diodes that can allow large level current to flow are also discussed. In addition, possible optimization strategies for these techniques are proposed for researchers' reference. This article will help researchers understand the current study status of vertical beta-Ga2O3 diodes and inspire researchers for future innovation in this emerging and exciting field. Moreover, the techniques and optimization strategies mentioned can also be applied to other semiconductors.