Piezoelectric Pressure Sensors for Hypersonic Flow Measurements

A microelectromechanical-system piezoelectric pressure sensor targeting hypersonic flow applications is presented. The sensing diaphragms have 500-mu m diameter and are comprised of a composite stack of Si, SiO2, and AlN. This paper presents the fabrication and packaging details of the sensor and then presents test results from a Mach-6 hypersonic-flow facility, in which the prototype sensor data are compared against data from a mature commercial sensor present in the same tests. Salient hypersonic-flow features are observed in signals captured by the prototype. The package is comprised of an on-chip two-element array with 650-mu m pitch, and signals from the elements captured during hypersonic-flow tests are highly correlated.