NiTi thin film characterization by Rutherford backscattering spectrometry

Nickel and titanium can form alloys showing the shape memory effect when combined in the right stoichiometric proportion (1:1). Recently, such alloys have been produced as thin films by sputtering (RF or DC, with or without magnetron), with a view to making microelectromechanical actuators. Precise control of the characteristic transformation temperature is crucial for obtaining the shape memory effect. This requires analytical tools which can accurately determine the relative composition, and hence the transition temperature. In this paper, Rutherford backscattering spectrometry will be shown to meet the requirements of thin film processing of NiTi shape memory alloys, and to have advantages when compared with other techniques.