(Invited) Materials Properties and Their Impact on Beta Gallium Oxide for High Power Electronics Applications

Abstract

Beta gallium oxide represents a promising material for high power device applications. However, the incorporation of this material into device structures is not as well understood as materials which have been used previously for high power device applications. Those materials (for example silicon, SiC, and GaN) possess crystal structures with higher symmetry. The monoclinic structure of beta gallium oxide leads to non-uniform thermal stresses in bulk and epitaxial layers and significant differences in reactivity due to surface orientations and doping levels. The low thermal conductivity of beta gallium oxide can be compensated by integrating it with other high conductivity materials. We address the crystalline perfection in state-of-the-art beta gallium oxide using high resolution x-ray scattering and topography techniques, the role of chemical mechanical polishing on sub-surface damage, the impact of the differences in thermal expansion coefficients along different crystallographic directions on gallium oxide structures in epitaxial systems, and initial studies into large scale exfoliation techniques for materials integration of gallium oxide with high thermal conductivity materials.