Modification of the Mechanical Properties of SiO2 Thin Film Using Plasma Treatments for Micro-Electro-Mechanical Systems Applications

Abstract

In this study, we developed a novel method of modifying thin-film mechanical properties by plasma surface modification. In order to demonstrate the feasibility of this approach, various plasma treatments, including exposure to O2, H2, and NH3 atmospheres, were implemented to modify the mechanical properties, including Young's modulus, residual stress, and hardness, of SiO2 films. The experimental results show that the mechanical properties have been changed following the formation of Si–N and Si–H bonds. These characteristics can be employed to change the shape and resonant frequencies of micromachined beams for micro-electro-mechanical systems (MEMS) applications. Since plasma treatment is simple and easy to integrate with existing processes, it has the potential to be an efficient way to finely modify the mechanical characteristics of MEMS structures.