Integrated piezoresistive pressure sensor and relative fabrication method

摘要

The pressure sensor is integrated in a SOI (Silicon-on-Insulator) substrate using the insulating layer as a sacrificial layer, which is partly removed by chemical etching to form the diaphragm. To fabricate the sensor, after forming the piezoresistive elements (10) and the electronic components (4, 6-8) integrated in the same chip, trenches (26) are formed in the upper wafer (23) of the substrate and extending from the surface to the layer of insulating material (22); the layer of insulating material (22) is chemically etched through the trenches (26) to form an opening (31) beneath the diaphragm (27); and a dielectric layer (25) is deposited to outwardly close the trenches (26) and the opening (31). Thus, the process is greatly simplified, and numerous packaging problems eliminated. <IMAGE> <IMAGE>