Liquid Crystal Alignment Properties of Inorganic SiO2 Layers Prepared by Reactive Sputtering in Nitrogen-Argon Mixtures

Abstract

According to the advent of ubiquitous world, the requirement for the mobile information devices with high display quality and compact device size is surprisingly increased. Among the diverse candidates for this mobile display system for mobile devices, Liquid Crystal on Silicon (LCoS) is the most competitive device due to the high aperture ratio and simple fabrication process. The inorganic liquid crystal (LC) alignment layers are widely used for LCoS devices because of the thermal and photochemical stability. In this work, the reactive sputtering was selected for the preparation method of inorganic LC alignment layers. The nitrogen (N2) gas had the effect on the deposition process of SiO2and the surface morphology of SiO2thin layers were affected by the N2mixing ratio of sputtering gas. In addition, the LC alignment properties on SiO2thin layer were also closely related with the N2mixing ratio and other sputtering conditions. In the case of high RF power of reactive sputtering, the N2mixing ratio has little effect on the LC alignment on SiO2thin layers. However, in the case of low RF power of reactive sputtering, the LC alignment properties were enfeebled by increasing the N2mixing ratio. This result might be attributed to the change of the surface morphology of inorganic SiO2thin layers.