Dry release of MEMS origami using thin Al2O3 films for facet-based device integration

In recent years, more and more research was conducted to explore smaller and smaller systems that become similar to an
actual micro/nano-robot. The major roadblock regarding their real world implementation is the highly restricted available
volume. In this paper, we introduce folding – hence an origami technology using Al2O3 as building material, which is
compatible with current Si technology. High quality 50 nm thin Al2O3 film is grown by atomic layer desposition, patterned,
thinned and then released from the Si subtrate using SF6 plasma etching. The realized free standing Al2O3 structure would
fold itself at predefined regions due to the stress in the as deposited films. We believe such technology could offer a new
possibility to tackle the problem of efficiently using the volume. Al2O3 could act as both the structural origami material and
the functional gate dielectric material for electronics. This approach enables the feasibility of patterning devices and circuits
on every Al2O3 facet of a 3D object, while the inside volume of this object is still available for 3D bulk device components.
We demonstrate the optimized etching process as well as an emperical improvement of the folding hinges and of the overall
structural stability.