Effect of substrate bias and hydrogen addition on the residual stress of BCN film with hexagonal structure prepared by sputtering of a B4C target with Ar/N2 reactive gas

Abstract

The effect of substrate bias voltage and hydrogen addition on the residual stress of BCN film with hexagonal structure (hBCN) was investigated. The hBCN films were deposited on silicon (100) substrates by the sputtering of a B4C target with a gas mixture of Ar (25 sccm) and N2 (5 sccm) at a chamber pressure of 0.27Pa. A compositional gradient B-C-N buffer layer was introduced before the deposition of the hBCN film. The compressive residual stress of the hBCN film was observed to decrease from 5.5GPa to 4.5GPa with the increase in the substrate bias voltage from −200V to −300V. By the addition of hydrogen (5 sccm), the compressive residual stress of the hBCN film deposited at a substrate bias voltage of −300V was observed to be reduced further to 3.0GPa. The stress reduction occurred in the hBCN film by an increase in the substrate bias voltage, and hydrogen addition is due to a change in the alignment of hBCN (0002) planes, which is closely related to the penetration probabilities of argon ions into the film.