Applications of Shape Memory Alloys in MEMS Devices

Abstract: The position control in shape memory alloys are difficult because of its non linear thermo mechanical behaviour, hence they are generally designed in two stable positions i.e. Austenite Phase ( High temperature state) and Martensite Phase ( Low temperature state). Shape memory alloys are the material that has the ability to retain to its original shape when heated. SMAs has high resistivity that produces joule heating effect when current is applied. TiNi SMA has many properties which make is it significant in MEMS devices. In this paper The NiTi - Si Shape memory thin film based based microcantilever was designed which has three stable positions. The effect of temperature over the NiTi-Si thin film based microcantilever and the effect of change of structural dimensions of cantilever is analysed. It demonstrates a way to have multiple stable positions in an SMA device, which can have some significant advantages in many real engineering applications..

Keywords: Joule heating , Microcantilever, Micro Electro Mechanical Systems (MEMS), Shape Memory Alloys (SMA), Titanium Nickel (TiNi).