Low temperature crystallised Ti-rich NiTi shape memory alloy films for microactuators

Obtaining low temperature crystallised NiTi films would ensure a good compa tibility with microelectronics processes and allow deposition on substrates that could not endure high temperatures, like polymers. We found that NiTi films containing an excess of Ti (52% at.) are crystallised when deposited on Si(100) substrates heated up to only 200 degrees C. Resistance vs. temp erature measurements show typical martensitic transformation behaviour. By depositing this type of films on polyimide substrates, we obtain bimorph mi cro-actuators exhibiting a two-way shape memory effect. (C) 1999 Elsevier S cience S.A. All rights reserved.