CONTROL COMPOSITION STUDY OF SPUTTERED NI-TI SHAPE-MEMORY ALLOY FILM

Since the transition temperature of the shape memory effect in NixTi1- x films depends on the composition of the layer, it is indispensable t o have an accurate control on their composition. We are now able to co ntrol in situ the composition of r.f. sputtered Ni-Ti films in the who le domain of shape memory effect (0.476 < x < 0.531). by varying the p roduct of sputtering gas pressure P and target-to-substrate distance d . Pressure measurements are found to give a good sensitivity for the c ontrol of Ti-rich layers, while the optical emission spectroscopy of t he sputtering plasma gives better sensitivity for Ni-rich layers.