Growth evolution of CaB6 thin films deposited by DC magnetron sputtering

CaB6 films were deposited by a DC magnetron sputtering method to explore the growth evolution systematically through changing sputtering time. The crystalline structure was characterized by XRD and GIXRD respectively, which showed that the films were anisotropic with nanocrystalline structure. The grain sizes increased with the deposition time, and a weak (100) texture appeared when the deposition time reached to 120 min. HRTEM was employed to demonstrate the crystalline structure. The surface morphology evolution of CaB6 films was analyzed by AFM and FESEM. The results showed that the films were initially formed by fine columnar grains. With the deposition time extended, the films exhibited a dense columnar structure with faceted surfaces. The grain size, film thickness and crystallization degree all increased with the sputtering time.