High-resolution pressure sensors fabricated by silicon wafer direct bonding

Silicon diaphragm pressure sensors have been fabricated on SOI structures to reduce the pressure sensitivity variation. The SOI structure, made by direct bonding two oxidised silicon wafer together, was used as an etch-stop layer during diaphragm formation and for controlling the diaphragm thickness. The pressure sensitivity variation can be controlled to within a standard deviation of +or-2.3% from wafer to wafer.