Effect of FIB milling on NiTi films and NiTi/Si micro-bridge sensor

Resonance based mass sensors are able to sense tiny fractions of grams based on the resonant frequency shift of a resonator when the resonator is subjected to changes in attached mass or temperature. In our work, NiTi/Si micro-bridge with a design of tunable resonance based sensor was successfully fabricated using Xe+ plasma focused ion beam (FIB). Before fabricating the micro-bridge, an influence of various Xe+ FIB currents on the transformational behavior of NiTi films was tested. In the other part of the present study, the effect of temperature on the vibrating NiTi/Si micro-bridge was examined in a broad range of frequencies. It is suggested that the NiTi film can work as a frequency tuning element in resonance based mass sensors. The shift of the first resonant frequencies of NiTi/Si bilayer micro-bridge with the length, width, thickness and the NiTi/Si thickness ratio being 200 ?m, 40 ?m, 5.8 ?m and 0.29, respectively, is up to 7% with temperature ranging from 25 C to 100 C during heating up. The finite element analysis of the micro-bridge is done in order to calibrate the NiTi/Si micro-bridge resonator sensor.