The diffusion barrier characteristics of electron cyclotron resonance (ECR) sputtered films were investigated by thermal desorption spectroscopy using O-3-tetraethoxysilane-based nondoped silicate glass films as diffusion sources of H2O and H-2 molecules. The ECR sputtered oxide films, SiO2 and Al2O3, have two modes of deposition, an oxide mode and a metal mode. The high quality film deposited by the oxide mode is suitable as a diffusion barrier against H-2, while the film deposited by the metal mode, which has a higher density of dangling bonds, is suitable as a diffusion barrier against H2O. Si3N4 and Al2O3 films act as better barriers than the SiO2 film. However, the film thickness dependence of the barrier effect was lost at about 340degreesC for the Si3N4 film and 400degreesC for the Al2O3 film; their diffusion barrier characteristics could not be evaluated above those temperatures. Although optical microscopy did not reveal any cracks in the films, the fact that the barrier effect of the films was lost suggests that microscopic cracks were induced by stress effects.