Abstract
Mesoporous silica films with two-dimensional cage structure were prepared on a silicon substrate by a vapor phase synthesis. Vapor of tetraethoxysilane (TEOS) was infiltrated into a surfactant film consisting of triblock copolymer. The mesostructure of the thin films was characterized by X-ray diffraction (XRD), Field emission scanning electron microscope (FE-SEM) and transmission electron microscope (TEM) observations. Nitrogen adsorption/desorption measurements were performed using films on the silicon substrate and powdery sample which was peeled from the silicon substrate. The mesostructured silica thin films have silicate layers with ordered pillars and are isotropic parallel to the film surface. The structure of pores of the films is of advantage for next-generation low-k films. The mesoporous structure has a large lattice parameter d of ~102Å, silica layer thickness of ~58Å, pillar diameter in the middle of ~60Å, pore size of ~72Å, BET surface area of ~729 m2/g, and pore volume of ~1.19 cm3/g. The films show high thermal stability up to 900°C and high hydrothermal stability. This method is a simpler process than conventional sol-gel techniques and attractive for mass production of a variety of organic-inorganic composite materials and inorganic porous films.
