Reducing stiction in Microelectromechanical Systems by nanometer-scale films grown by atomic layer deposition

Stiction during device operation remains one of the mechanisms leading to permanent failure of operating silicon-based MEMS devices (MicroElectroMechanical Systems). The goal of this work was to investigate, whether stiction between parallel, smooth silicon surfaces can be decreased by thin inorganic films grown by atomic layer deposition (ALD). Test structures based on the cantilever-beam-array (CBA) method were fabricated and coated with ALD layers varying in chemical nature and roughness. Rough crystalline TiO₂ decreased the adhesion energy orders of magnitude as compared to Si and other smooth films, indicating that TiO₂ and other crystalline ALD films are candidates for anti-stiction layers in MEMS.