A silicon-on-insulator (SOI) substrate structure and method of fabrication including a single crystal silicon substrate, a layer of single crystal rare earth oxide formed on the substrate, a layer of engineered single crystal silicon formed on the layer of single crystal rare earth oxide, and a single crystal insulator layer of IIIOxNy formed on the engineered single crystal silicon layer. In some embodiments the III material in the insulator layer includes more than on III material. In a preferred embodiment the single crystal rare earth oxide includes Gd2O3 and the single crystal insulator layer of IIIOxNy includes one of AlOxNy and AlGaOxNy.