Various embodiments of the invention relate to methods and systems for
thermal compensation of a MEMS device. In certain embodiments, an
interferometric modulator includes a first electrode and a flexible
second electrode situated on a substrate. The flexible second electrode
is a movable layer that can comprise aluminum or an aluminum-containing
material, while the substrate can comprise glass. When the
interferometric modulator undergoes a temperature change, the difference
in thermal expansion rates results in a decrease in the tensile strain on
the movable layer. Embodiments of the present invention provide a film
configured to compensate for the thermal expansion. The film has a
thermal expansion coefficient less than the substrate so as to compensate
for expansion of the movable layer with respect to the substrate when the
MEMS is exposed to thermal energy. The film compensates for mismatch in
thermal expansion between the materials of the substrate and movable
layer so as to inhibit undesirable optical characteristics.