Temperature effects in Au piezoresistors integrated in SU-8 cantilever chips

Abstract

We present a cantilever-based biosensor chip made for the detection of biochemical molecules. The device is fabricated entirely in the photosensitive polymer SU-8 except for integrated piezoresistors made of Au. The integrated piezoresistors are used to monitor the surface stress changes due to binding of biomolecules on the surface of the cantilever. Here we present the characterization of the chip with respect to temperature changes in the surrounding environment. Furthermore, self-heating of the piezoresistors due to the applied voltage over the resistors is investigated including the temperature increase of the cantilever surfaces. The obtained results indicate that although low voltages of about 0.5–1 V are required to avoid self-heating of the cantilevers, surface stress changes below 1 mN m−1 can still be detected. The results are compared to previously presented results for Si-based cantilevers.