SIMS, RBS and glancing incidence X-ray diffraction studies of thermally annealed Ru/β-SiC interfaces

Thermal stability of the Ru/β-silicon carbide (SiC) interfaces up to 800 °C is investigated using secondary ion mass spectrometry (SIMS), Rutherford backscattering spectrometry (RBS) and glancing incidence X-ray diffraction (GIXRD) studies. The objective of this work is to assess the potentiality of ruthenium to be used as a stable gate metal of the Schottky junction gas sensors working at high temperature. The SIMS and RBS studies indicate no significant change in the interface after short-term as well as long-term annealing at 400 °C, the optimum operating temperature of the Ru/β-SiC (epilayer on Si) Schottky junction gas sensors. Glancing incidence X-ray diffraction study does not detect any silicide formation at the Ru/SiC interface after heat treatment at this temperature. However, annealing the junction at a substantially higher temperature (800 °C) results in the formation of ruthenium silicides at the interface over a narrow region along with the oxidation of the top few Ru layers.