Characterization of ternary Al-B-N films

Abstract Boron nitride under equilibrium conditions crystallizes in the sp 2 bonded graphite like structure and therefore shows no solubility with aluminum nitride or the other group III nitrides. An incorporation of BN into the wurtzite lattice of AlN could extend the applications of (Al,Ga,In)N films due to a higher variability concerning band gap and lattice parameters. To investigate the regions of metastable solid solubility between AlN and BN, ternary films with compositions along the quasibinary section AlN-BN have been deposited on Si(111) wafers at substrate temperatures of 100 and 600°C by means of reactive magnetron sputtering. The structure and texture of the films have been analyzed by reflection high energy electron diffraction (RHEED) after the transfer of the films in a lock chamber under high vacuum into the analysis chamber. In the same device, the composition and binding states were measured by photoelectron spectroscopy (XPS, XAES). The lattice parameters of the films have been determined using X-ray diffraction with a grazing incidence attachment (GIXRD). The results show that it has been possible to deposit by reactive magnetron sputtering metastable single-phase (Al,B)N films in the sp 3 bonded wurtzite structure of AlN with BN contents of at least 33 mol.%. The films are strongly textured with different [ h 0 l ] textures for deposition at 100°C substrate temperature and [001] textures at 600°C. The crystallinity, especially of the BN rich films, increases with higher temperatures.