RF-SPUTTER DEPOSITION OF BORON-NITRIDE THIN-FILMS

Rf-sputter deposition was performed using a hexagonal boron nitride (h-BN) target in a reduced atmosphere on a silica glass substrate at 700-degrees-C. Oxygen impurity in the films enhances their oxidation. Hydrogen (5 vol.%) was added to the nitrogen sputter gas to remove oxygen impurity from the films. Sputter deposition was performed in a gas pressure range of 6-60 Pa. The film obtained at 6 Pa was white, opaque, and could easily be scraped off from the substrate. X-ray diffraction showed that the film was turbostratic (t-) BN. With increasing gas pressure, the films became opaque and crystallized to h-BN. The film obtained at 60 Pa was a mixture of t-, h- and cubic (c-) BN. Low signal levels for X-ray diffraction and IR absorption make the identification of c-BN inconclusive. However, the signal levels increased under the deposition conditions of high substrate temperature, high gas pressure, and addition of H-2 to the sputter gas.