ALD honeycomb plates enabling robust ultrathin MEMS

This paper reports rigid MEMS structures made of ALD films, which had thicknesses as low as 10 nanometers and were patterned in the shape of a 3D honeycomb. Hexagonal honeycomb lattices offer a dramatically higher flexural stiffness compared to that of planar films, allowing us to fabricate large-area suspended devices without significant warping. Both alumina (Al₂O₃) and silica (SiO₂) structures were fabricated, each presenting a different set of fabrication challenges. The spring constants of the cantilever structures were measured and compared with the simulation results.