Fabrication of cantilevers with high yield for magnetic resonance force microscopy

A fabrication method of ultra-sensitive cantilevers with high yield of almost 100% is presented. The oxide layer of an SOI wafer is patterned before the bulk silicon etching. It would break at the patterned place, while the bulk etching was to the end, which could avoid the cantilevers breaking. The SOI wafer is putted in a PTFE container during etching and cleaning. We moved the container from liquid to liquid instead of moving the wafer. These two steps ensured the high yield of almost 100% of the cantilevers. The cantilevers could detect forces as small as 10−17 N/Hz1/2 with dimensions of 465×10×0.47μm3 in a vacuum chamber at room temperature. The force sensitivity is believed to be much better at low temperature. The field gradient of three types of magnets is researched based on simulation. A conical magnet with small dimensions would be a good choice for spin moment detection in MRFM applications.