Electron-assisted deposition of cubic boron nitride by r.f. magnetron sputtering

Cubic boron nitride (cBN) has been deposited on silicon (100) substrates by means of radio frequency (r.f.) magnetron sputtering in nitrogen using a hexagonal boron nitride target with the assistance of a simultaneous electron bombardment of the growing surface. Unlike most thin-film deposition processes for cBN, intentional bombardment of the growing surface by ion beams within specific ranges in energy and flux is not required for this process to achieve high-purity cBN films. Fourier transform infra-red (FTIR) spectra of cBN films show a strong absorption band around 1070 cm^-1. With electrons bombarding the growing surface at a current density of 140 mA cm^-2 or higher, pure (according to FTIR spectra) cBN films are deposited on silicon substrates at temperatures above 750"C. The effects of electron current density and nitrogen gas pressure on the synthesis of cBN films will be discussed.