Fabrication of Silicon-Based Shape Memory Alloy Micro-Actuators

Abstract

Thin film shape memory alloy has been integrated with silicon in a new actuation mechanism for micro-electro-mechanical systems. This paper compares nickel-titanium film with other actuators, describes recent results of chemical milling processes developed to fabricate shape memory alloy micro-actuators in silicon, and describes simple actuation mechanisms which have been fabricated and tested.

The effect of crystallizing procedure on microstructure and characteristics of sputter-deposited TiNi shape memory thin films

“…In order to further improve the properties of the TiNi films, a good deal of attention has been paid to their processing, microstructure, residual stress and phase transformation behaviors in recent years [5][6][7][8]. The TiNi films used to be prepared by sputter deposition onto silicon substrates [9] and they have to be crystallized for the SME. The crystallizing procedure will certainly affect the microstructure and properties of the sputter-deposited films.…”

Composition and structure of NiTiCu shape memory thin films

“…After being deformed at low temperature, a piece of NiTi is able to return to its initial memorized shape by annealing: this is the property of shape memory. NiTi shape memory alloy (SMA) films possess numerous qualities: they can sustain high stresses (500 MPa) without permanent deformation [1], they can be controlled by low voltage [2], they have an important work/weight ratio [3] and they are biocompatible materials [3,4]. As miniaturization continues in modern technology, so does the need for smaller and better actuators.…”