The nuclear reaction from low-energy deuteron-bombardment has proved to be a valuable tool for surface oxide layer examination. Using the16O(d, p)17O and16O(d, α)14N reactions, some important properties of Si−SiO2 structures, such as total number of oxygen nuclei and oxygen concentration profile, can be determined in one measurement with an accuracy of several percent, within one hour. Some effects of oxygen deficiency in SiO2 layers of thicknesses exceeding 6000 Å have been found. A more detailed study of this effect will be the subject of forth-coming experiments.