METHOD AND APPARATUS FOR A DIRECT BONDED ISOLATED PRESSURE SENSOR

摘要

A pressure sensor (100, 222) integrally formed in the shape of a beam (102) around a central channel. The beam (102) has an integral blind end (104) that is pressurized by the fluid. The beam has an opposite end (106) that is shaped to provide a stepped corner (107) with a gap (108) opening at the base of the stepped corner (107), where the gap (108) and isolated from the fluid. A sensing film (112) in the channel adjacent the blind end (104) has an electrical parameter that varies with pressure and electrical leads (110) that extend from the channel and out the gap. A seal (115) fills the gap (108) around the leads (110) and the seal (115) fills a portion of the stepped corner (107). The sensor (100) is preferably formed by direct bonding of single crystal alumina layers (114, 116). Applications include industrial pressure transmitters, aerospace and turbine engine pressure sensing.