Piezoresistive Silicon Diaphragm Mechanical Stress Mitigation Techniques
Mitigating piezoresistive pressure diaphragm stress requires Pyrex pedestal isolation, compliant die-attach selection, and multi-point thermal matrix trim.
Long Term Zero Drift
Output Change
Gradual change in the output signal of a sensor over an extended period while the input remains constant. This long term zero drift measures the aging of components and the slow relaxation of internal stresses within the device package. The shift is measured in units of the sensing variable per unit of time and determines the frequency of required re-calibrations.
Aging Factor
Chemical degradation of sensing materials and the migration of dopants in semiconductors contribute to this phenomenon. Over months or years, long term zero drift can cause the baseline of a sensor to wander heavily from its factory settings. These slow shifts are distinct from short-term noise or thermal fluctuations which occur on much shorter timescales.
Operational Impact
Maintaining accuracy in autonomous systems requires sensors with minimal levels of this error. If long term zero drift is not monitored, the system may provide increasingly inaccurate data that leads to mission failure or safety risks. Precision applications often use redundant sensors to detect and compensate for the individual drift of each component.
This strategy ensures that the overall system performance remains within acceptable bounds even as individual parts begin to age.
Specification Limit
Manufacturers provide a maximum value for this parameter in the technical datasheet. Testing involves logging the output of the sensor under controlled conditions for several thousand hours.