Highly sensitive pressure sensor using Au patterned polydimethylsiloxane membrane for biosensing applications: Correlation of sensitivity and effective sensing range with membrane thickness

A highly sensitive pressure sensor using gold film patterned on polydimethylsiloxane (PDMS) membrane has been developed and characterized. Strain induced changes in Au film resistance was used to perform quantitative measurement of absolute pressure. Typical sensitivities of the sensors with 3 mm x 3 mm footprint, fabricated using 50, 100, and 200 μm thick PDMS films, were found to be very high at 0.1/KPa, 0.056/KPa and 0.012/KPa, yielding very high gauge factors of 370, 180 and 70, respectively. We found that the device sensitivity and effective sensing range for reliable operation are closely correlated with the PDMS membrane thickness. Thinner membrane offers higher sensitivity but lower effective sensing range, which presents us a design tradeoff for desired sensor performance. This experiment observation also corresponds well to the results obtained from COMSOL based finite element simulation.