Fabricating Diamond Membranes Using Reactive-Ion Etching

A process for the fabrication of a polycrystalline diamond membrane involves chemical vapor deposition (CVD) of diamond onto a silicon substrate, followed by conventional photolithography and subsequent reactive-ion etching to remove part of the substrate (see figure). This process is an improvement over an older process in which the substrate is etched in a hot KOH solution. This process can be used to fabricate diamond polycrystalline membranes as parts of microelectromechanical sensors.