Patterning of diamond microstructures by bulk and surface micromachining for MEMS devices

In this paper, diamond microstructures were patterned over silicon/silicon dioxide substrate using the processes combined with bulk or surface micromachining, selective growth of diamond and plasma etching technique. Polycrystalline diamond films were prepared using microwave plasma enhanced chemical vapor deposition (MW-PECVD) and a gas mixture of hydrogen and methane. Two types of techniques for precise patterning of diamond microstructures were investigated in this paper. The first one was to selectively grow diamond films in the desired region by pre-depositing a Pt interlayer on silicon dioxide layer. The second one was to selectively etch the deposited diamond film in oxygen/argon plasma under an Al mask. Different microstructures, for example, microgear, microrotor, comb drive structure, etc. were successfully fabricated.