Atomic layer deposition of conformal dielectric and protective coatings for released micro-electromechanical devices

This paper describes a novel fabrication approach using Atomic Layer Deposition (ALD) of dielectric materials to protect and coat released MEMS devices. The nature of ALD film ensures coverage on all sides of a released MEMS device and is done at a relatively low temperature (down to 150/spl deg/C). The ALD film thickness can be precisely controlled as each reaction cycle deposits approximately one monolayer of atoms. To demonstrate the concept of conformal layer deposition, alumina (Al/sub 2/O/sub 3/) was deposited onto released MEMS devices prior to electrostatic testing. Curvature and increase in beam stiffness for coated MEMS devices were investigated.