Synthesis of cubic boron nitride film by inductively coupled plasma CVD technique

Boron nitride (BN) films were deposited at different substrate temperatures (623-773 K) on Si substrates by inductively coupled plasma chemical vapour deposition (CVD) technique using borane-ammonia as the boron containing precursor gas. FTIR studies indicated the films to contain mixed phases of cubic BN (c-BN) and hexagonal BN and the percentage of c-BN was dependent on the deposition environment. The optimum deposition condition for obtaining a higher c-BN phase (>90%) was ascertained. Borane-ammonia vapour was diluted with nitrogen and argon and the dependence of the nature of plasma species at the plasma-substrate interface on the c-BN content was ascertained. The surface texture of the films was observed by scanning electron microscope and atomic force microscope. Ellipsometric studies were carried out to determine the optical constants of the films.