Effect of thin film interconnect inelasticity on MEMS pressure sensor hysteresis

Thermal hysteresis dominates precision errors in absolute low pressure piezoresistive Silicon-based MEMS

pressure sensors. A population of 10 experimental unpackaged “floating” bare devices were subjected to pressure and

temperature cycles resulting in a mean hysteresis error of initially 0.062 % of full scale (FS) that reduced to 0.036 %FS after

the third cycle. Within the limited 5 to 65 °C thermal cycles used in this study, this hysteresis is not predicted by the elastic

recovery regime and is attributed to low temperature creep phenomena caused by stresses, that develop as a result of the

coefficient of thermal expansion (CTE) mismatch between the Al-1 %Si bond pads and the Si substrate.