FORMATION OF NANOCRYSTALS IN BCN THIN-FILMS DEPOSITED BY RADIOFREQUENCY PACVD

Boron-carbon-nitrogen (BCN) coatings were deposited on Si (100) substr ates by r.f. plasma-assisted chemical vapour deposition (PACVD). Dimet hylamine borane vapour was used as a precursor and an argon-hydrogen m ixture as plasma gas. For the first time crystals were observed in BCN -films prepared by PACVD. All the BCN-coatings deposited by PACVD repo rted in the literature were amorphous and hydrogenated. The films were characterized with High Resolution Transmission Electron Microscopy ( HRTEM), Electron Spectroscopic Imaging (ESI), Electron Energy Loss Spe ctroscopy (EELS), FT-IR spectroscopy, Auger Spectroscopy (AES) and X-r ay Photoelectron Spectroscopy (XPS). The results of the different anal ysis methods indicate with a high probability the formation of cubic c rystals containing boron, carbon and nitrogen. Of great interest is th e possibility that these crystals form a c-BN/diamond alloy phase. The influence of the substrate temperature (from 200 degrees C to 850 deg rees C) and of the gas composition, especially the hydrogen content, o n the growth of the crystals are discussed.