LOW-TEMPERATURE DEPOSITION OF CUBIC BN-C FILMS BY UNBALANCED DIRECT-CURRENT MAGNETRON SPUTTERING OF A B4C TARGET

Controllable-unbalanced de magnetron sputtering of a B4C target in mix ed Ar-N-2 discharges has been used to deposit BN:C thin films with car bon concentrations in the range of 5-21 at, % on Si(001) substrates. T he variation of the nitrogen gas consumption with nitrogen partial pre ssure was used to determine the sorption capacity of the sputtering so urce and was then correlated to the film discharge plasma density near the substrate in a wide range. Hence, the ion flux J(i) of primary Ar + and N-2(+) ions accelerated to the substrate by an applied negative substrate bias could be varied while keeping the deposition flux J(n) (the sum of film building species, B, C, and N atoms) near constant. B N:C films were grown at large ion-to-neutral flux ratios 3 less than o r equal to J(i)/J(n) less than or equal to 24, ion energies E(i) less than or equal to 500 eV, and substrate temperatures 150 less than or e qual to T-s less than or equal to 350 degrees C. The phase and element al composition of as-deposited BN:C films were characterized by Fourie r transform infrared spectroscopy and wavelength dispersive x-ray spec troscopy, respectively. Deposition of cubic phase c-BN:C containing 5- 7 at. % of C is demonstrated under conditions of low energy (110 eV) i on bombardment, a high ion-to-atom arrival rate ration (J(i)/J(n) simi lar to 24), and low growth temperatures (similar to 150 degrees C). (C ) 1996 American Vacuum Society.