Stress and Silicon Nitride: A Crack in the Universal Dissipation of Glasses

Abstract

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 $255\text{ }\text{ }\ensuremath{\mu}\mathrm{m}\ifmmode\times\else\texttimes\fi{}255\text{ }\text{ }\ensuremath{\mu}\mathrm{m}\ifmmode\times\else\texttimes\fi{}30\text{ }\text{ }\mathrm{nm}$ thick high-stress ${\mathrm{Si}}_{3}{\mathrm{N}}_{4}$ membrane reveals that the dissipation ${Q}^{\ensuremath{-}1}$ decreases with lower temperatures and is $\ensuremath{\simeq}3$ 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 ${Q}^{\ensuremath{-}1}$, violating the universality of dissipation in disordered materials in a self-supporting structure.