プラズマCVD法による硬質アモルファス窒化ホウ素膜の作製

Abstract

Boron nitride deposits were prepared on Si substrates using a glow discharged plasma chemical vapor deposition apparatus with a gas mixture of BCl3-N2-H2-Ar and characterized using some evaluation techniques for their morphology, atomic composition, crystal structure and mechanical properties. The deposition apparatus used in this study is equipped with an rf plasma source for Ar-N2 gas mixture excitation, and a heater for decomposition of BCl3. This films were deposited on the substrate at the conditions of a total gas pressure of 266 Pa and an rf power of 100 W for the plasma operation. The dendritic aggregation of hexagonal BN (h-BN) and amorphous boron-rich boron nitride film were contained in the deposits. The dendritic aggregation of h-BN had a size of approximately 10 μm and grew along the scrached mark. In addition, the boron-rich amorphous film had a thickness of 3 μm as a result of 1.8 ks-deposition. A substrate temperature of ≥673 K and a negative bias voltage applied to the substrate of ≥350 V are required in obtaining high deposition rate of amorphous films. The surface of amorphous films indicated a Knoop hardness of Hk6000-8000 at a loading force of 98 mN. Furthermore, the scratching test revealed that the critical load of the amorphous films was larger than that of diamond-like carbon films prepared on the Si substrate. These results suggest that the amorphous boron nitride film obtained in this work is one of the candidates for hard coating material.