TiNi Shape Memory Alloys for MEMS: Thin Film Deposition, Thermophysical Properties and Laser Micromachining Characteristics
The growth of TiNi thin films by ion beam sputter deposition using a Kaufmann type ion source is described. Argon ions are used to sputter separate Ti and Ni targets to deposit nearequiatomic TiNi thin films. Typically, ion energies and current densities of 1500 eV and 1 mA cm-2 respectively are used, with an argon overpressure of around 0.05 mtorr, to achieve deposition rates of order 1 μm hr-1. The thermophysical properties of the deposited films were investigated by thermal imaging. Patterning of TiNi films and foils with micrometre resolution using KrF excimer laser ablation at 248 nm wavelength, with beam fluence up to 2.5 J cm-2, 15 ns pulse duration and pulse rates up to 100 Hz has also been investigated.
T. Chandra, K. Tsuzaki, M. Militzer , C. Ravindran
S.T. Davies "TiNi Shape Memory Alloys for MEMS: Thin Film Deposition, Thermophysical Properties and Laser Micromachining Characteristics", Materials Science Forum, Vols. 539-543, pp. 3151-3156, 2007