Preparation and characterization of c-BN films by RF sputtering

Boron nitride films for SAW devices were deposited on Si (100) wafers by RF magnetron sputtering. To prioritize the main influencing factors of the c-BN content, an orthogonal experiment was designed. The c-BN and h-BN phases in films are tested by Fourier transform infrared (FTIR); The surface morphologies of films are characterized by atomic force microscopy (AFM). Result of the FTIR indicates that the sequence of influential significance can be arranged as follows: Substrate temperature>; Ratio of N₂: Ar>; Sputtering power>; Substrate negative bias. High content of c-BN thin film was prepared with substrate temperature of 575°C, N₂: Ar ratio of 8:8, sputtering power of 300W and substrate negative bias of -100V. The AFM result indicated that the surface morphology of films are smooth with lower roughness.