Solid-state reactions between iridium thin films and silicon carbide in the 700 °C to 1000 °C temperature range

The solid-state reactions between iridium thin films (50 nm) and 6H‐SiC in the 700–1000 °C temperature range were investigated. The microstructure and surface morphology of the Ir thin films on 6H‐SiC were examined using Rutherford backscattering spectrometry (RBS), scanning electron microscopy (SEM), Raman spectroscopy and grazing incidence X-ray diffraction (GIXRD). The electron beam deposited Ir films had a polycrystalline structure with the (111) preferred orientation and their crystallinity increased with annealing temperature. The Ir films were stable and did not interact with the SiC substrate after annealing at temperatures below 800 °C. The RBS results indicate that the initial reaction at 800 °C was very fast and almost the entire 50 nm film had reacted leading to the formation of Ir-rich silicides, Ir3Si2 and IrSi. After annealing at 900 and 1000 °C, the RBS profiles XRD results showed that the solid-state reactions proceeded further and Ir3Si2 was converted to IrSi. At the final annealing temperature of 1000 °C the predominant phase was IrSi. Thermodynamic analysis of the reaction phases confirmed the formation and sequence of the phases observed.