Reliability of gyroscopes based on piezoresistive nano-gauges against shock and free-drop tests

Piezoresistive sensing through Si gauges of sub-micrometric cross-section represents an alternative to capacitive sensing in MEMS inertial sensors, potentially advantageous from a miniaturization point of view. Nevertheless, no reliability data against mechanical shocks and drops were presented for such type of technology so far. This work performs an experimental characterization campaign which includes shock tests up to 3400 g (gravity units) and free-drop tests in ceramic package, for 10 Z-axis plus 10 Y-axis gyroscopes based on nano-gauge readout. The results indicate 100% survivability rate to these experiments, verified through comparative modal analyses before and after the test. The results further demonstrate rate sensitivity changes after 10 free drops (onto marble surface) lower than 0.8%, a value within the characterization setup accuracy.