Mechanical and electrical properties of Amorphous Silicon Nitride thin films for MEMS

Abstract

Besides well-established markets such as automotive, microelectromechanical systems (MEMS) devices are readily integrated in a growing number of consumer, industrial, and medical applications. The diversity of these application scenarios often demands the fulfilment of very specific requirements with respect to the materials being implemented. The engineering of thin film material systems enables to deliver tailored solutions that are both optimal for the application, and for a later commercialization in the ideal case compatible with existing CMOS technologies. Silicon nitride (SiNx) thin films have found their use in microelectronic and MEMS devices as standard materials in various functionalities, including electrical isolation, capping passivation, optical waveguides and structural-mechanical layers. Despite their widespread usage and associated experience, SiNx thin films still offer a large untouched potential by exploiting the full flexibility of certain deposition processes. In this work, amorphous silicon nitride films were synthesized using two different plasma processes: inductively coupled plasma chemical vapour deposition (ICP-CVD) and reactive magnetron sputter deposition. The deposited samples were characterized using a wide range of analytical equipment with regards to their mechanical, optical and electrical properties, as well as their chemical composition.