Atomic mixing at metal–oxide interfaces by high energy heavy ions

Abstract

We study the atomic mixing at metal (Bi or Au)/oxide (SiO2 or Al2O3) interfaces under 150–200MeV heavy ion irradiation. Irradiation-induced interface mixing state is examined by means of Rutherford backscattering spectrometry (RBS). For Bi/Al2O3 interfaces, the heavy ion irradiations induce a strong atomic mixing and the amount of the mixing increases with increasing the electronic stopping power for heavy ions. By comparing the results with that for 3MeV Si ion irradiation, we conclude that the strong atomic mixing observed at Bi/Al2O3 interfaces is attributed to the high-density electronic excitation. On the other hand, for other interfaces (Bi/SiO2, Au/Al2O3 and Au/SiO2), atomic mixing is rarely observed after the irradiation. The dependence of atomic mixing on combinations of irradiating ions and interface-forming materials is discussed.