Modelling and fabrication of low operation temperature microcages with a polymer/metal/DLC trilayer structure

Multi-finger microcages with metal/diamond like carbon (DLC) bilayer and polymer/metal/DLC trilayer structures were analyzed, simulated and fabricated. Modelling by finite element analysis showed that a soft polymer can be used together with DLC to form a normally closed microcage which can be opened by 90° angle at a temperature of ∼400 K, which is much lower than that of a metal/DLC bilayer structure previously demonstrated. The opening temperature for a microcage is independent of the finger dimensions, but is simply determined by the thermal expansion coefficient difference of two materials used. Microcages with SU8/DLC bilayer and SU8/Al/DLC trilayer structures have been fabricated and fully closed microcages with diameters of ∼40 μm have been obtained. Initial electrical tests have showed these devices open by more than 90° at a temperature lower than 150 °C, roughly in agreement with the theoretical analysis.