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 O 2 , H 2 , and NH 3 atmospheres, were implemented to modify the mechanical properties, including Young's modulus, residual stress, and hardness, of SiO 2 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. © 2008 The Japan Society of Applied Physics.