Influence of atomic layer deposited coatings for MEMS applications: a review

Abstract

This paper reviews the influence of coating MEMS devices using atomic layer deposition (ALD) to produce nanometer-thin films. It has recently become a subject of great interest for ultrathin film deposition in many various applications such as microelectronics, photovoltaic, dynamic random access memory (DRAM), and microelectromechanical system (MEMS). Atomic layer deposition (ALD) is a thin film growth technique that utilises alternating, self-saturation chemical reactions between gaseous precursors to achieve deposited nanoscale layers. The ALD process is capable of depositing a variety of thin-film materials to protect MEMS devices from electrical break down, mechanical wear and stiction failure. ALD ensures conformal film coverage on all sides of the MEMS device and can be performed at relatively low temperature. The ALD film thickness can be precisely controlled at the atomic level as each reaction cycle deposits approximately one atomic monolayer. It facilitates surface deposition on a variety of substrates that have low melting temperature. Eventually it could contribute to widen nanoscale MEMS applications and be advantageous in other emerging areas.