Influence of rapid thermal treatment on the mechanical properties of submicrostructures based on nickel and chrome films

The results of a study of the phase composition, surface morphology, grain size and mechanical properties of submicrostructures based on chromium and nickel before and after rapid thermal treatment (RTT) at temperatures from 200 to 550 °C are presented. Surface morphology and grain size were determined using atomic force microscopy. Mechanical properties were determined by nanoindentation. Rapid thermal treatment of nickel and chromium films significantly affects the change in phase composition, surface morphology, grain size and properties. The formation of silicides (according to the diffusion mechanism) and new phases occurs in the films: the CrSi 2 phase is formed at temperatures of 350 °C and above, the Ni 2 Si phase at 300 °C, and the NiSi phase at 350 °C and above. When the phase composition changes, the grain size increases. In the RTT ranges from 200 to 300 °C and from 450 to 550 °C for chromium-based submicrostructures, the correlation between microhardness and grain size is carried out according to the Hall–Petch law – microhardness increases with decreasing grain size. For nickel-based submicrostructures, the Hall–Petch law is satisfied in the temperature range from 200 to 300 °C and from 500 to 550 °C. In the temperature range of 300–450 °C for chromium-based submicrostructures and 300–500 °C for nickel-based submicrostructures, microhardness decreases with decreasing grain size and vice versa, i.e. a “negative Hall– Petch effect” occurs. This effect is associated with the phase transitions Cr → CrSi 2 and Ni → Ni 2 Si → NiSi, restructuring of submicrostructures due to the diffusion mechanism, morphological rearrangement of vacancy defects and annealing of point defects inside grains, as well as the corresponding reconstruction of grain boundaries. The considered submicrostructures based on chromium and nickel can be used in microelectronics for Schottky diodes, ohmic contacts and gates.