MECHANICAL-PROPERTIES OF SINXCY CERAMIC FILMS PREPARED BY PLASMA CVD

The mechanical properties of Si3N4-SiC, SiN(x) and SiCy films prepared at a low temperature of 400-degrees-C by plasma chemical vapour deposition are reported. Microhardness, internal stress of the film and adhesive strength between the film and glass or stainless steel substrate were evaluated as principal mechanical properties. Microhardness was measured to be about 10 to 20 GPa dependent on the film composition in each system. Internal stress of the films on borosilicate glass substrates extensively varied from tensile to compressive with the film composition change from Si3N4 to SiC. Adhesive strength, as ascertained by the scratch test, was about 580 to 800 MPa for crown glass substrates, and about 210 to 310 MPa for 316 stainless steel substrates. It is pointed out that tensile stress in these films brought about more abrupt decreases of the adhesive strength than did compressive stress.