GaAs-on-insulator fabricated via ion-cut in epitaxial GaAs /Ge substrate

A novel approach of combining ion-cut and selective chemical etching for the fabrication of high-crystalline -quality GaAs-on-insulator has been proposed. Epitaxial GaAs/Ge layers were grown via molecular beam epitaxy (MBE), exhibiting superior GaAs/Ge interface and surface properties suitable for wafer bonding. A lower dose about 8×10¹⁶ H⁺/cm² was implanted into Ge bulk substrate instead of high-dose of 2×10¹⁷ H⁺/cm² into GaAs to thermally induce splitting. The exfoliation of the Ge and transferring of the GaAs layer onto the silicon oxide were realized through room temperature bonding and annealing temperatures as low as 350°C, followed by ICP etching of the residual Ge sacrificial layer exposured to SF₆. The GaAs-on-insulator was finally achieved with lower dose implantation and a rather smooth surface with a RMS roughness ~0.246 nm.