In Situ Thermal Aging Calibration Corrections for High Temperature MEMS Transducer Arrays
Dynamic matrix corrections combine in situ reference tracking and Arrhenius modeling to eliminate unbudgeted high temperature MEMS recalibration cycles.
Thermal Aging
Degradation Vector
Systematic exposure of sensor materials to elevated temperatures for an extended duration accelerates the degradation mechanisms that cause long-term performance drift. This process, known as thermal aging, is utilized during both qualification testing and production burn-in to stabilize the sensor before field deployment. Measuring the change in device characteristics before and after exposure allows manufacturers to quantify the stability of the system.
Stress Profile
Accelerating the aging process requires the selection of a test temperature that is high enough to stimulate the degradation mechanisms without inducing new, unrealistic failure modes. Arrhenius equations are commonly used to calculate the equivalent operating lifetime simulated by a short-term, high-temperature test cycle.
Material Drift
Diffusion of dopants, grain boundary relaxation, and oxidation of thin films during thermal exposure drive the drift of the sensor offset and sensitivity. These physical changes alter the electrical resistance or mechanical stiffness of the sensing elements, resulting in a shift in the calibration curves.
Lifetime Projection
Long-term drift curves plotted from the aged samples provide the basis for estimating the operational life and drift tolerances of the sensor. Devices that exhibit drift rates exceeding the specified limits are rejected during the quality control stage.