:: IPCI ::

Two conductive silicon wafers are bonded together
Silicon wafers form both the mechanical part and capacitor electrodes and therefore
no metalised electrodes are required
Dielectric spacer serves for the electric insulation between the electrodes
and for the gap thickness definition
Such a solution reduces the thermal drift of the sensor and simplifies the processing
Top silicon substrate has been etched to form corrugations in the diaphragm
to define the behaviour of the diaphragm under pressure
Thickness of the SiO₂ layer determines the gap between the electrodes
and therefore the base capacitance of the device
Relatively thick membrane corrugated on the edges reduces the degree of bending
across the top electrode and thus improves the sensor linearity

Capacitive pressure sensor fabricated with surface-micromachining techniques

Movable electrode of the transducer can be made made of polysilicon, Si_xN_y or other material
Fixed electrode is realized as the metallized surface of the silicon substrate
No bonding process is needed