On the temperature compensation of parallel piezoresistive microcantilevers in CMOS biosensor

Microcantilever with embedded piezoresistor has been applied to in situ surface stress measurement of biochemical reaction, where the parallel microcantilever by using an active cantilever for biosensing and another reference cantilever for noise cancellation has previously been proposed. This paper shows that the microcantilever measurement is sensitive to the temperature effect induced by the piezoresistor. The two cantilevers of 125 μm × 60 μm × 0.75 μm may have 40 °C temperature difference, 1.65 mV offset voltage, and 0.01 mV/°C temperature drift in 10 V operation because of their different thermal inertia. A parallel microcantilever design is developed for temperature compensation by using a signal conditioning circuit and the stripe pattern immobilized layer. Analyses and experiments show that the performance of parallel microcantilever sensor can be significantly improved.