Oxidation of Al/Si by Microwave Excited O2 + N2 Mixture Plasma

Al thin films evaporated on Si were oxidized in a microwave excited O2 + H2 mixture and O2 + N2 mixture plasmas, where H2 or N2 was added as a catalytic gas. The compositional variation of each element with depth and the chemical structure of the film were analyzed by means of IMA and XPS with Ar-ion sputtering. In O2 + N2 mixture plasma, an evident interfacial oxide layer was observed at the interface. In O2 + H2 mixture plasma, the inner SiO2 layer was not recognized. To explain these experimental findings, a tentative model of oxidation process is proposed taking into account of electronegativity.