Crystal Strain
Mechanical compression within a semiconductor substrate arises directly from the mismatch of thermal expansion coefficients between silicon and the packaging materials that encapsulate it during fabrication. Thermal excursions induced during solder reflow or anodic bonding generate shear forces that distort the piezoresistive response of integrated Wheatstone bridges. Operating limits are established by manufacturers at room temperature under zero external loading conditions, beyond which nonlinearity begins to corrupt output signals.
Calibration routines must separate packaging induced offset shifts from true inertial deflection to maintain certified performance parameters across industrial temperature ranges.
Crystal Migration
Residual lattice distortion relaxes over time through microscopic dislocations within the silicon lattice, causing zero-point drift in high precision accelerometers. Packaging adhesives continue to cure long after initial production concludes, transferring dimensional shifts straight into active sensing elements. Environmental chambers accelerate this aging process during factory screening, yet post-installation relaxation still introduces long-term offset errors that require periodic recalibration.
Stress Hysteresis
Thermal cycling forces piezoresistive elements through continuous mechanical loading loops that rarely return the crystal lattice to its exact initial state. Friction at the die attach interface traps residual energy within the substrate, creating non-reproducible output errors during subsequent measurement cycles. Metrologists quantify this phenomenon by comparing sensor zero points before and after standardized thermal shock sequences.
Substrate Distortion
Package cavity geometry dictates how external mechanical mounting forces transmit through the housing walls and warp the underlying silicon footprint. Uneven torque applied during printed circuit board assembly bends the substrate, altering the baseline capacitance of parallel plate actuators. Verification protocols rely on laser interferometry to map surface topology changes before final sealing takes place.
