High-throughput membrane deflection characterization of shape memory alloy thin films

Abstract

Nickel–Titanium (Ni–Ti) shape memory alloy thin films are currently gaining significant attention for small-scale systems, but device integration is still challenging due to its high compositional-dependent behavior. Therefore, it is crucial to identify the optimal parameters required to fabricate desirable samples. In this study, combinatorial high-throughput membrane deflection experiments were performed to investigate the mechanical properties of submicron-thick Ni–Ti thin films. The mechanical properties of freestanding Ni–Ti thin films, sputter-deposited with compositions and thicknesses ranging from 45.7 at. % to 52.7 at. % nickel and 270–530 nm were evaluated. With an increase in the Ni content, the crystallinity and existing phases of the films varied and exhibited an overall increasing trend of elastic modulus, transformation stress, percentage of recoverable strain and hysteresis area. Based on the obtained results, the compositional ratio of Ni–Ti films can be tailored accordingly to meet the different requirements of small-scale devices, and to then extend the employment of this high-throughput methodology in exploring advanced metallic alloys and ceramic composites.