Substrate surface effect on the structure of cubic BN thin films from synchrotron-based X-ray diffraction and reflection

► BN films with different substrate roughness were analyzed by synchrotron X-rays. ► More cBN phase formed near the surface than substrate in the as-deposited film. ► With substrate roughness increase, more hBN phase formed in the film. ► Synchrotron-based GI-XRD and XRR are powerful tools for characterizing BN films.