Batch fabrication of metal oxide sensors on micro-hotplates

We report the parallel fabrication of miniaturized chemical sensors by the direct integration of nanostructured transition metal oxide films onto micro-hotplate platforms based on micromachined suspended membranes. This has been achieved by local deposition on a 10 × 10 membrane wafer of a supersonic cluster beam through a microfabricated auto-aligning silicon shadow mask. The sensing properties of the obtained devices were tested with respect to various gaseous species. For reducing and oxidizing species such as ethanol and NO2, very good performance in terms of linearity and sensitivity was observed. These results demonstrate the feasibility of the coupling of a bottom-up nanofabrication technique such as supersonic cluster beam deposition to a top-down microfabricated platform for a direct and parallel integration methodology of nanomaterials in MEMS.