Fabrication of free standing LiNbO(3) single crystal micro-platelets and their integration to Si-on-insulator platforms

Abstract

Free standing single crystal LiNbO3 micro-platelets (mm long and 1 mu m thick) have been obtained from a z-cut LiNbO3 wafer by ion implantation and thermal treatment. X-ray diffraction measurement has proved that they have a single crystal structure. Their surface roughness and film quality have been investigated by atomic force microscope and field emission scanning electron microscope. These micro-platelets are transferable and bondable to other materials which require material properties of LiNbO3. They have been transferred, positioned and bonded to SiO2/LiNbO3, SiO2/Si, and Si-on-insulator (SOI: Si/SiO2/Si) by direct bonding method with optimum annealing conditions. For SiO2/Si and SOI substrates, there were large thermal mismatch between LiNbO3 and Si. They were, however, bonded at high temperature since these ultra thin microplatelets were flexible and stretchable. Finally, to realize multifunctional SOI applications, a hybrid structure of LiNbO3 film and Si waveguide has been demonstrated. (C) 2011 Elsevier B.V. All rights reserved.