#2 Technological developments of 3C–SiC thermal devices

The precedent chapter established the remaining technological bottlenecks for the development of a scalable SiC-based thermal sensor activity, which can be summed up by the difficulty to produce electrically insulated, suspended SiC wires.

In this chapter, several technological approaches to fabricating SiC thermal anemometers are explored. Since our research group has no prior experience in micromachining silicon carbide, etching and patterning routines for 3C–SiC were established first. This enabled to fabricate simple clamped-clamped SiC beams (section ¿sec:etching-process?). Then, the current leaks through the SiC/Si interface were noticed, and ways to overcome this effect were investigated (section ¿sec:electric-insulation?): mechanical thinning and transferring to a glass wafer, working with poly-SiC deposited on a SoI wafer, and using an intermediate “buried layer” of low-doped 3C–SiC as an insulating layer. Iterating on this steps, a calorimetric WSS prototype sensor was fabricated (section ¿sec:fabrication-calorimeters?) using each insulating method, and with different doping configurations. A test bench was built in order to characterize the fabricated sensors (section ¿sec:characterizations?), i.e. measure the wires’ resistance, its dependence relative to the temperature and their TCR.