Hard Amorphous Si-B-C-N Films with Ultra-High Thermal Stability in Air

摘要

Novel quaternary Si-B-C-N materials are becoming increasingly attractive because of their possible high-temperature and harsh-environment applications. In the present work, amorphous Si-B-C-N films were deposited on Si and SiC substrates by reactive dc magnetron co-sputtering using a single C-Si-B or B_4C-Si target in nitrogen-argon gas mixtures. Films deposited under optimized conditions (B_4C-Si target, 50% N_2 + 50% Ar gas mixture) exhibited extremely high oxidation resistance in air at elevated temperatures (even above 1500 °C).Formation of protective surface layers (mainly composed of Si and O) was proved by high-resolution transmission electron microscopy (HRTEM), Rutherford backscattering spectrometry (RBS) and X-ray diffraction (XRD) measurements after oxidization.