As seen from this equation, the sensitivity can be increased
by increasing the area, or by reducing the polyimide thickness.
Because ultrathin polyimide films have been used in devices
reported here, it is possible to reduce the area of the sensor and
still obtain a relatively large capacitance change in response to
changes in humidity. A number of much smaller sensors have
also been fabricated. One sensor is 110 m 110 m with the
top electrode fingers being 10 m wide and 10 m spacing, and
another sensor is 55 m 55 m whose fingers are 5 m wide
with a 5 m spacing