A study on characteristics of micro-porous silica films prepared by aerosol flame deposition

Porous silica thin films were prepared on silicon wafers by an aerosol flame deposition (AFD) process, and dependence of their characteristics on sintering temperature was investigated. At sintering temperatures ranging from 1270 °C to 1320 °C, films with continuous micro-pores were deposited. As the sintering temperature increased, the pores of the film were getting smaller with more uniform distribution and the thickness and surface roughness decreased. The films were found to be hydrophilic when tested by the sessile drop method and the captive bubble method. And, zeta potentials of the films in a KCl solution sharply decreased to the minimum value at pH 8 and increased again as pH increased. The minimum value for the film prepared at sintering temperature of 1320 °C was −87 mV.