Sensor with silicon strain gage

摘要

A media-compatible sensing structure (210) that employs strain-sensing elements (222) formed in or on a silicon chip (212). The sensor (210) generally includes a metal body (214) having a diaphragm (216) and an edge (226) formed by an abrupt change in the thickness of the metal body (214) in a direction normal to the diaphragm (216). The silicon chip (212) is secured directly to the metal diaphragm (216) and has at least one strain-sensing element (222) aligned with the edge (226) of the body (214) in the direction normal to the diaphragm (216), such that movement of the diaphragm (216) induces strain in the silicon chip (212) that is localized at the strain-sensing element (222). The chip (212) preferably includes a groove (234) in its surface (212) facing the diaphragm (216) and between the strain-sensing element (222) and the metal body (214), such that strain induced in the chip (212) by movement of the diaphragm (216) is further concentrated in the region of the chip (212) containing the strain-sensing element (222). The chip (212) is preferably attached to the metal diaphragm (216) with a bonding material (236). To promote adhesion of the chip (212) to the diaphragm (216), the chip (212) preferably has recesses (240) in its surface facing the diaphragm (216) to create an interlocking effect between the bonding material (236) and the chip (212).