Routes towards the epitaxial integration of gallium oxide with silicon

We report on the structural properties of Ga2O3 grown by plasma-assisted MBE on STO, STO-buffered Si (001) and gamma-alumina buffered Si (001). The integration of Ga2O3 with Si can lead to a lowering in cost of Ga2O3 wafer production, enable monolithically-integrated devices and gives the low-thermal conductivity material Ga2O3 a platform with higher thermal conductivity. The grown structures were investigated by XPS, RHEED, XRD, XRR and HRTEM. On STO (001) and STO-buffered Si (001), the growth planes (-112) and (100) of beta-Ga2O3 are observed, on gamma-alumina which takes the (111) orientation on Si (001) the (-201), (101) and (310) growth planes of beta-Ga2O3 are observed. Common theme that guides the epitaxial relationship is a matching of the (distorted) cubic centered oxygen sublattice of beta-Ga2O3 to the sublattice of the oxide (pseudo-)substrate. Since beta-Ga2O3 has a low symmetry monoclinic structure multiple in-plane orientations of the films are observed with respect to the substrate.