A method for making a pressure sensor by providing a wafer including a
base silicon layer, a buried sacrificial layer, and a top silicon layer.
The top silicon layer is arranged over the buried sacrificial layer and
the buried sacrificial layer is arranged over the base silicon layer.
Etching vents through the top silicon layer to the buried sacrificial
layer and removing a portion of the buried sacrificial layer. Depositing
silicon to seal the vents and arranging a strain gauge or a capacitance
contact on the wafer. A method for making a pressure sensor including
providing a bulk wafer and depositing a sacrificial layer on the bulk
wafer. Depositing silicon on the sacrificial layer and the bulk wafer to
form an encapsulation layer. Etching vents through the encapsulation
layer to the sacrificial layer and removing the sacrificial layer.
Closing the vents with a silicon deposition and arranging a strain gauge
or a capacitance contact on the encapsulation layer. A pressure sensing
device including a substrate, an encapsulation layer with vents, and
voids between the substrate and the encapsulation layer. A portion of the
encapsulation layer above the voids forms a membrane and deposited
silicon plugs fill the vents. A strain gauge or a top capacitive contact
arranged on the membrane.