  This paper reports the application of zinc oxide (ZnO) in the pressure
sensors that can be integrated with a microelectromechanical system (MEMS). ZnO
is one of the materials that has received a great deal of attention due to its
unique properties of being a semiconductor with wide bandgap and piezoelectric
effects. The simpler crystal growth mechanisms of ZnO have resulted in a lower
cost of ZnO-based sensors. Different types of pressure sensors based on ZnO
sensing elements have also been explored. A thin circular ZnO film was
simulated as a piezoelectric sensor employing the finite element method in
COMSOL. The pressure applied on the thin film surface was varied and a boundary
point probe was used to study the displacement field and voltage at the center
of the membrane. The displacement field and voltage induced by pressure vary
linearly with increasing pressure on the ZnO layer. Also. the method used in
this paper was applied to different piezoelectric materials, such as barium
titanate (BaTiO3), polyvinylidene fluoride (PVDF), and gallium arsenide (GaAs)
that were studied by other groups, and similar conclusions were made. These
simulations can be used in the design of piezoelectric sensors and the
optimization of the sensitivity and performance of the materials used in
pressure sensor applications.
