Ion beam mixing at copper/alumina interfaces using marker geometry

Abstract

In the present paper results on ion beam effects such as ion beam mixing, radiation enhanced diffusion (RED) and phase stability in Cu Al 2O 3 marker interfaces are presented. Cu/Al 2O 3/Cu samples with marker geometry were prepared by vapor deposition of copper and alumina on polished glassy carbon and single crystal silicon substrates. The top Cu layer had a thickness of 70 nm and the marker thickness was 2.5 nm. In case of the Al 2O 3/Cu/Al 2O 3 samples a 2.5 nm Cu marker followed by an amorphous alumina layer with a thickness of 110 nm and a density of 2.9 g/cm 3 were deposited on single crystal alumina substrates. The marker samples were irradiated with 150 keV Ar + ions. Ion doses were in the range of 1.1 × 10 16 to 5.4 × 10 16 Ar +/cm 2. The sample temperature was varied between room temperature and 673 K. The mixing of the marker layers with the matrix was analyzed by depth profiling using Rutherford backscattering spectroscopy (RBS). Additionally, in case of the alumina marker system, to measure the aluminium depth distribution, nuclear reaction analysis (NRA) was applied using the 27Al(p, γ) 28Si reaction with a resonance energy of 992 keV. Film stability was checked by scanning electron microscopy (SEM)