Patent ID: 6973835

Claim:
A method of manufacturing a micromachined pressure sensor, including the steps of: providing a first silicon substrate, forming a cavity recess in an upper surface of the first silicon substrate, the cavity recess being a lower part of a reference chamber to be formed, providing an closing structure including a monocrystalline silicon layer, bonding the first silicon substrate at the upper surface to the monocrystalline silicon layer, thereby closing the cavity recess and forming the reference chamber, removing material or part of the closing structure, the portion of the closing structure covering the cavity recess forming a diaphragm, and forming a sensor path, in particular of a strain gauge or piezoresistive gauge, sensing movements of the diaphragm, characterized in that in the step of providing a closing structure a SOI-structure is provided to include a second silicon substrate carrying on a surface thereof the monocrystalline silicon layer and an inner electrically isolating layer, in particular an inner silicon oxide layer, placed between the second silicon substrate and the monocrystalline silicon layer, and that in the step of removing material or part of the closing structure all the material of the second silicon substrate is removed, in particular etched away, so that a portion of only the monocrystalline silicon layer forms a substantial portion of the diaphragm, in particular a supporting or structural part of the diaphragm.