Fabrication of TiNi shape memory alloy microactuators by ion beam sputter deposition

We report on the production of thin films of TiNi shape memory alloy, grown by ion beam sputter deposition (IBSD) using a Kaufman-type source, for microactuator applications. IBSD is a vacuum-coating process in which a target is bombarded by accelerated ions from a showered ion beam source and sputtered atoms of the target material are deposited onto a nearby substrate. In this work, argon ions at energies up to 1500 eV and current densities of are used to bombard sectored targets of titanium and nickel in order to deposit TiNi films onto unheated substrates. The films were characterized by electrical resistivity measurements and x-ray reflectometry. R-phase and martensitic transformations are seen without high-temperature annealing and the shape memory properties are compared with those of films prepared by DC and RF magnetron sputtering.