Abstract
This thesis is dedicated to a comprehensive study on stress of various films and composite structures such as bilayer and sandwich structures. The film materials, including silicon nitride (SiNxHy), silicon dioxide(SiO2), and silicon oxynitride (SiON), all deposited by plasma enhanced chemical vapor deposition(PECVD) technology. We focus on the influence of deposition parameters and annealing to uniform stress and gradient stress of the films, discussing what happens to the bending moment of the cantilever beams. We try to use the concept of stress compensation to fabricate low stress and flat cantilever beams. We observed that various single layers are hard to fabricate flat cantilever beams due to the difficulties of the control of gradient stress. For bilayer structures, as a result of the different directions of the stress of upper and lower layers, there will exist a large bending moment, leading the extent of bending of the cantilever beams more serious. And for sandwich structures, we can make quite flat cantilevers by adjusting the thickness of each layer.