Pablo Espinosa Argaiz (The University of Texas at Austin)

"Epitaxial Growth of Gallium Oxide over MgO and STO Buffered Silicon via Sputtering Deposition"

Abstract: Gallium Oxide (Ga2O3) is a wide-bandgap semiconductor with promising applications in power electronics due to its high electron mobility and high breakdown electric field. Nevertheless, these properties are limited by its poor thermal conductivity, which leads to excessive Joule heating in high-power applications. Epitaxial integration of Ga2O3 on more thermally conductive substrates is key for the efficient operation of Ga2O3 based electronic components. Silicon is a promising candidate for such integration, as it has good thermal conductivity and is readily available in high-quality bulk substrates. However, Ga2O3 cannot be epitaxially grown directly on Silicon as their interface is not thermodynamically stable. The integration of Ga2O3 and Silicon can be made possible through buffer layers. Strontium Titanate (SrTiO3) and Magnesium Oxide (MgO) are two metal oxides which can be grown epitaxially on Silicon and can serve as an effective buffer layer to grow Ga2O3. While we have demonstrated that Ga2O3 successfully grows on both buffer layers, our results show that the crystal quality can be improved. The epitaxial relationship between Ga2O3 and the buffer layers will be presented, as well as the deposition methods and characterization of the grown films. Additionally, further ideas for improving the crystal quality of the Ga2O3 films will be discussed.