DISTINGUISHING THIN-FILM AND SUBSTRATE CONTRIBUTIONS IN MICROINDENTATION HARDNESS MEASUREMENTS

Microhardness measurements were carried out on silicon, boron, boron nitride, and nickel films deposited on polished stainless steel substrates. A titanium diboride film on a sapphire subsubstrate was also examined. It is shown that a log-log plot of indentation size versus applied load (the Meyer plot) reveals the point at which the substrate begins to influence the hardness measurements. The ratio of indentation depth to film thickness at the critical point varied from 0.06 to 0.4 depending on both film and substrate hardness. The microhardness numbers differ from those calculated from data in the composite (film plus substrate) region by proposed formulas. © 1990, American Vacuum Society. All rights reserved.