A new method for the characterization of the longitudinal and transverse strain sensitivities of conductive thin films for their use in microsensors

摘要

This work explores a new method for measuring the absolute (longitudinal and transverse) strain sensitivity of conductive strain thin-film gages deposited on silicon structures. Strain gages are integrated at key positions of the diaphragm submitted to constant pressures where points of zero radial strain and near-zero angular (circumferential) strain can be defined over the surface of a pressurized diaphragm. The strain sensitivities of gold and semimetal thin films are determined, in view of their inclusion as strain gages. An anomalous behavior of the semimetal films is highlighted for it allows us to fabricate strain gages of sensitivities much larger than metallic counterparts and approximately equal to those exhibited by semiconductor materials such as silicon. The patterning (by chemical etching) of the semi-metal films and electrical contacts is developed as part of the process for the fabrication of microelectronic circuits and micro-sensors.