A conduction–convection model for self-heating in piezoresistive microcantilever biosensors

Abstract

Thermal drifting caused by the self-heating in piezoresistive microcantilever biosensors is a major source of inaccuracy. To this use, the present study derives a simple and accurate conduction–convection model to predict the temperature distribution in p-doped piezoresistive microcantilevers because of self-heating. The model is applied to a 4-layer gold-coated piezoresistive silicon dioxide microcantilever biosensor with u-shaped silicon piezoresistor. The analytical results are compared to the numerical results. The effect of convective heat transfer coefficient on temperature profile is also studied. The comparison results show the analytical and numerical results are accurate within 4%. The sensitivity results showed that the resistance change produced by thermal drifting is about five-to-eight times that by the surface stress. Finally, the cantilever temperature profile is found to be strongly affected by the piezoresistor size and the convective heat transfer coefficient.