• Fifteen years have passed since I started development of β-Ga2O3 crystal growth technique and power devices. In the early stages of our research, we prototyped MESFETs or SBDs using extremely small epitaxial wafers of about 4 mm square or less that were fabricated using the floating zone method and the molecular beam epitaxy. We have now reached the stage of mass production of 4-inch wafers by using the edge-defined film fed growth (EFG) method and halide vapor phase epitaxy (HVPE) method. And we are also preparing for mass production of β-Ga2O3 SBDs using 4-inch process foundry.
     

  • Exploiting the unique properties of gallium oxide for power electronics requires control over doping, not only in Ga2O3 itself but also in AlGaO3 alloys [1], which are required for the modulation-doped heterostructures used in devices. We need adequate n-type conductivity in the channel, and the ability to achieve semi-insulating layers. First-principles modeling, using advanced hybrid functional calculations within density functional theory, can shed light on all aspects of this process. 
     

  • This first decade of monoclinic Ga2O3 device research has been incredible (underpinned by the availability of large area bulk substrates) in breakdown voltages, power device figure of merit and high-speed performance. It has emerged as a promising ultra-widebandgap semiconductor for next generation power, GHz switching and RF applications. The large bandgap of Ga2O3 leads to a high critical field strength. This high field strength in combination with demonstrated room temperature mobility and calculated electron velocity leads to higher Figures of Merit (BFoM/JFoM) than current commercially available WBG technologies. Additionally, the large bandgap also enables high temperature operation and radiation hardness making it attractive for space applications such as Mars and Venus missions.