Field Emission Characteristics of BN Films Treated with H₂ and O₂ Plasma

BN films were synthesized on the (100)-oriented surface of n-Si (0.008--0.02Ωm) by rf magnetron sputtering physical vapor deposition (PVD). A BN film was first treated with H₂ plasma for 60min and then the H₂ treated sample was treated with O₂ plasma for 15min. The films were characterizes by using Fourier transform infrared spectra (FTIR) and atomic force microscopy (AFM). The field emission characteristics of BN films were measured in an ultrahigh vacuum system. A turn-on electric field of 8V/μm and a current of 400μA/cm² were obtained for the BN film treated with H₂ plasma. The results show that the surface plasma treatment makes no apparent influence on the surface morphology of the BN films. The transformations of the sample emission characteristics have to do with the surface negative electron affinity (NEA) of the films possibly. The turn-on electric field of the BN film treated with H₂ plasma is lower than that without treatment, which possibly attributes to the surface NEA effect. The surface NEA of the H₂ treated BN film is lost after O₂ plasma treatment.