Effect of sputtering condition on the surface properties of silicon oxide thin films prepared for liquid crystal alignment layers

Abstract

SiO x thin films are widely used for the LC alignment layer for LCoS devices due to the thermal and photochemical stability of SiO x . In this work, the relationship between the sputtering condition and the LC alignment properties of SiO x thin films was studied. The physical and chemical properties of SiO x thin films were closely related with the RF power and the working pressure of RF-magnetron sputtering. The surface energy of SiO x thin films was mainly connected with the chemical composition of the SiO x thin films and the behavior of LC molecules on the SiO x thin films was dominantly affected by the surface energy. The azimuthal anchoring energy and the pretilt angle of LC molecules were changed by modifying the amount of oxygen atom in the SiO x thin films. By controlling the sputtering condition of SiO x thin films, it was possible to control the orientation of LC molecules on the SiO x thin films.