Nanoscale Mechanical Structures Fabricated from Silicon-on-Insulator Substrates

We describe a method with which to fabricate sub-micron mechanical structures from silicon-on-insulator substrates. We believe this is the first reported method for such fabrication, and our technique allows for complex, multilayer electron beam lithography to define metallized layers and structural Si layers on these substrates. The insulating underlayer may be removed by a straightforward wet processing step, leaving suspended single crystal Si mechanical structures. We have fabricated and mechanically tested structures such as beam resonators, tuning-fork resonators, and torsional oscillators, all with smallest dimensions of 0.1-0.2 microns and fundamental resonance frequencies above 10 MHz.