Optimization of the Electrodes Fabrication for Suspended Microchannel Resonators

Suspended microchannel resonators are precise sensors for single cell mass measurement. Although several actuation methods exist, the ANEMS Lab at EPFL developed a piezoelectrical (PZE) actuation/detection offering the benefits of on-chip transduction. The PZE, aluminum nitride (AlN), is sandwiched between platinum (Pt) electrodes and not fully patterned for a better performance of the device. However, the wet etching process, needed to access the bottom electrode, left occasionally some residues that would prevent good electrical contact. This project aims to investigate the reasons of this poor reproducibility by comparing the wet etching results on different combinations of photoresist, pattern sizes and top layer material. It was suspected that certain processes (e.g. ion beam etching) were more likely to be the cause. Furthermore, an additional chlorine chemistry dry etching step was tested to determine its potential benefits.