Direct measurement of the direction of interface motion in the oxidation of metals and covalent solids—Al(111) and Si(100) oxidation with O2 at 300 K

Four point probe measurements of the surface electrical resistance at an oxide film–metal interface and at an oxide–film semiconductor interface have shown with Å sensitivity that the direction of the buried interface motion during oxide film growth is opposite in the two cases in accordance with the Mott–Cabrera theory. During the formation of amorphous Al2O3 layers on Al(111) at 300 K, outward film growth occurs due to Al3+ ion transport from the metal into the growing oxide film. For the formation of amorphous SiO2 layers on Si(100) at 300 K, oxygen transport occurs inwardly into the Si lattice as the oxide film forms.