Free standing single-crystal silicon microstructures

Micromachined structures of single-crystal silicon have been fabricated with a view to developing them for a number of potential uses. The structures which are fabricated in (111) orientation silicon are undoped thus permitting the incorporation of active circuit elements in the structures themselves. Moreover no high temperatures, applied voltages or long etch times are used in the fabrication sequence, thereby simplifying the task of integration with circuit processes. The potential uses of these structures include photodiodes with high speed and efficiency, accelerometers, or structures for stress or thermal isolation.