Plenary Speakers

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.