Phosphosilicate glass (PSG) films were deposited onto silicon substrates by the oxidation of SiH4 and PH3  at 350°. Densities, phosphorus oxide concentrations, and infrared absorption spectra were measured for the evaluation of the film structure. It was found that nearly all the phosphorus oxide in a PSG film containing more than about 8 mole per cent P2O5 was dissolved into water by exposing to saturated water vapor at 120°C. By heating at elevated temperatures, the phosphorus oxide concentration value at which phosphorus oxide began to dissolve shifted toward the higher concentration region. Water absorption in the PSG film also can be lessened considerably by heat‐treatment.

Structural properties of Si films formed by chemical vapor deposition onto amorphous SiO2 substrates have been examined over the temperature and thickness ranges of 650 to 900°C and up to 1 µm respectively. At 650°C the films were amorphous regardless of their thickness. At 700°C the 0.1 µm-thick films were amorphous, but the <110> preferred orientation developed as the film thickness increased. Above 750°C 0.1 µm-thick films were seen to have a random orientation, and with increasing film thickness above 0.3 µm, the <100> and <111> orientations developed in the temperature ranges of 750 to 825°C and 825 to 850°C respectively. The influence of heating at elevated temperatures on film strutucres is also presented.

The structure of a silicon dioxide film deposited on a silicon substrate by oxidation of silane at 340°C was analyzed by using electron-diffraction and infrared absorption techniques. The Si–O, O–O, and Si–Si distances were determined by the radial-distribution analysis to be 1.62, 2.6, and 3.1 Å, respectively. The deposited film consists of SiO4 tetrahedra, but its atomic arrangement is more irregular than that in a thermally grown silicon dioxide film. As the deposited film is heated in nitrogen at 1000°C, the density increases and approaches that of thermally grown silicon dioxide film. No change occurs in average atomic distance by heating, but the atomic arrangement approaches that in the thermally grown silicon dioxide film. This is also explained from the narrowing of the Si–O–Si bending vibrational band near 450 cm−1 (22 μ) in the infrared-absorption spectrum.

Electron diffraction data have been used to obtain the radial distribution functions of thermal oxide films of silicon. Influence of multiple scattering of electrons on the intensity was taken into consideration, and a method of correcting for this effect was proposed. The Si–O, O–O, and Si–Si distances were determined to be 1.62, 2.60, and 3.1 Å, respectively. The angle of Si–O–Si bond was estimated to be 147±10°. The shape of an infrared absorption spectrum of the oxide film in a wave number range between 400 and 1,300 cm-1 was similar to that of fused silica. The atomic arrangement in the film is a three-dimensional random network consisting of SiO4 tetrahedra. Such an atomic arrangement is compared with that of fused silica.

The occurrence of crystallites in thermal oxide films of silicon is studied in connection with contamination by sodium and with surface irregularities on silicon, using reflecting electron diffraction technique. Crystallites formed under the presence of sodium are identified as α- and β-cristobalite. When sodium of about 1015 atoms/cm2 is deposited on the silicon surface before oxidation, the crystallites of a size discernible even by the naked eye are formed in the oxide films at 1100°C. The area of the crystallized region in the oxide film is proportional to the amount of sodium on the silicon surface before oxidation. When a lapped or sand-blasted silicon wafer is oxidized, the grown oxide film is noncrystalline, as well as the chemically etched and mechanically polished wafers.