Tin oxide films with highly preferred orientation along <101 axis were grown on Si(100) substrate by using reactive ion assisted deposition method. The impinging average ion energy per depositing Sn atom was changed from 10 to 100 eV/atom. Oxygen content in the deposited tin oxide films increased as average impinging ion energy were raised. The maximum XRD peak intensity appeared when the average energy of about 50 eV/atom was applied. From quantitative Auger electron spectroscopy, characteristic transitional Auger peaks of Sn MNN were shifted to lower kinetic energies as much as 4 ∼ 6±1.0 eV as the Sn4+ component became dominant in the deposited tin oxide films. On the basis of a tin 3d core level spectra analysis by XPS, it was determined that a sizable chemical shift of 1.0±0.02 eV occurred between stannous tin(Sn2+:SnO) and stannic tin(Sn4+:SnO2). The optical transmittance was also measured in the wavelength range from 200 to 800 nm for tin oxide films deposited on BK7 glass substrate.