Relaxation Parameters of Cu/substrate Type Coated Systems Under Nanoindentation

Abstract

In this work, we studied the relaxation parameters, he-p and hres, of three composite structures Cu/LiF, Cu/MgO, and Cu/Si, which have different types of a chemical bond between the substrates (ionic (LiF), ionic-covalent (MgO), and covalent (Si)) and differ in hardness (HCu = 0.6 GPa, HLiF, HMgO and HSi are 1.2, 7.5 and 8.2 GPa, respectively). For each type of substrates, coated systems (CSs) were fabricated with a following Cu film thickness: t1 = 85; t2 = 470 and t3 = 1000 nm. The behavior of relaxation parameters was examined over a wide range of loads, P = 2–900 mN, during nanoindentation. The elastic-plastic parameters were shown to depend on the CS type, as well as on the film thickness and the magnitude of the applied load.