Stress and silicon nitride: A crack in the universal dissipation of glasses
High-stress silicon nitride microresonators exhibit a remarkable room temperature Q factor that even exceeds that of single crystal silicon. A study of the temperature dependent variation of the Q of a 255Î¼mÃ—255Î¼ mÃ—30nm thick high-stress Si3N4 membrane reveals that the dissipation Q-1 decreases with lower temperatures and is â–¡ 3 orders of magnitude smaller than the universal behavior. Stress-relieved cantilevers fabricated from the same material show a Q that is more consistent with typical disordered materials. e-beam and x-ray studies of the nitride film's structure reveal characteristics consistent with a disordered state. Thus, it is shown that stress alters the Q-1, violating the universality of dissipation in disordered materials in a self-supporting structure. Â© 2009 The American Physical Society.