Surface Texturing Using Gold Nanoparticles to Reduce Adhesion in MEMS

Since the advent of Micro-electromechanical systems (MEMS) technology, researchers have used surface texturing as one of the approaches to alleviate unintentional adhesion in MEMS. However, the conventional methods used for surface texturing are reported to reduce apparent in-plane adhesion only by a factor of 20. Further, the test surfaces used to-date are inherently rough, as a result of which, the effects of surface texturing could not be studied independently. We report on a novel method of texturing inherently smooth Si(100) surfaces by depositing dodecanethiol capped gold nanoparticles using a gas-expanded liquid technique. The dodecanethiol capping ligands are removed by exposing the treated surfaces to UV-Ozone atmosphere for an hour and the textured surfaces thus obtained are characterized by atomic force microscopy (AFM) and scanning electron microscopy (SEM). The textured Si(100) surfaces exhibit a significant reduction in apparent in-plane work of adhesion, which is determined using the cantilever beam array (CBA) technique, compared to untextured smooth Si(100) surfaces having only native oxide on them.