Studies on the stress and thermal properties of Mo/B₄C and Mo_xC_1-x/B₄C multilayers

A comparative study of Mo/B₄C and Mo_xC_1-x/B₄C multilayers deposited by DC magnetron sputtering technology was presented in this paper. Using a homemade real-time stress measure instrument, the stress of two kinds of multilayers was investigated. Characterizations of the multilayers before and after annealing were performed by grazing incident and at-wavelength near-normal incident x-ray reflectivity. Experimental results show that after replacing Mo by Mo_xC_1-x, Mo_xC_1-x/B₄C multilayers obtain relatively smaller compressive stress compared with Mo/B₄C multilayers. The corresponding stress value changes from −0.99 GPa to −0.36 Gpa. Mo_xC_1-x/B₄C multilayers have also proven to have better thermal stability up to 600 °C. After repeatedly annealing from 100 °C to 600 °C, Mo/B₄C multilayers had a ∼2% decrease in near-normal incident reflectivity, while Mo_xC_1-x/B₄C multilayers had a smaller 1.4% loss of reflectivity and a higher stability temperature. (paper)