PREPARATION OF C-BN CONTAINING FILMS BY REACTIVE RF-SPUTTERING

Reactive r.f. sputtering by use of a hexagonal boron nitride (h-BN) target has been successfully used to deposit boron nitride films. The substrate temperature did not exceed 300-degrees-C. It was found that the films contained c-BN only if they were sputtered reactively in an Ar-N2 mixture at sufficiently negative self bias values. As a measure for the c-BN content the relative extinction coefficient Q(c) of the infrared absorption band near 1060 cm-1 was used. The maximum of c-BN content could be estimated for films prepared at 3% N2 in the working gas. Furthermore Q(c) increased with increasing deposition time, indicating changes in the growth mechanism. Analytical studies supported the suggestion that the films have an amorphous-like structure. Films containing a high content of c-BN partially delaminated quite often from the silicon substrates. However, the lack of adhesion could not be correlated to the internal stresses. The wear resistance of the c-BN containing films was clearly higher than that of h-BN deposits.