AI 中文总结
本研究针对纳米机械氮化硅谐振器的表面损耗问题，采用超高真空热处理方法，将其本征品质因数提升最高20倍，为开发下一代超高相干纳米机械谐振器提供了新途径。
AI 中文摘要
自耗散稀释效应被发现以来，氮化硅（SiN）纳米机械谐振器已成为超高相干机械系统的标杆，几何与应变工程推动其f·Q乘积取得显著提升。然而，表面损耗始终是主导且基本未解决的耗散通道。本文展示了一种与几何无关、直接针对表面损耗的方法：超高真空热处理。在1000℃下处理后，经耗散稀释的SiN膜谐振器的本征品质因数提升了最高20倍，表面损耗降低8倍，同时拉伸应力增大。光热红外光谱与原位X射线光电子能谱将该性能提升归因于热活化的硅醇缩合——即表面羟基端基转化为硅氧烷桥；品质因数与应力在可控湿度下的可逆性，证实了该效应源于表面化学。这些结果确立了表面化学可作为下一代超高相干纳米机械谐振器的可调参数。
英文摘要
Since the discovery of dissipation dilution, silicon nitride (SiN) nanomechanical resonators have set the benchmark for ultracoherent mechanical systems, with geometry and strain engineering driving remarkable gains in the $f \cdot Q$ product. Surface loss, however, has remained the dominant and largely unaddressed dissipation channel. Here, we demonstrate a geometry-independent approach that directly targets surface loss: thermal treatment in ultrahigh vacuum. Treatment at 1000$^{\circ}$C enhances the intrinsic quality factor of dissipation-diluted SiN membrane resonators by up to a factor of 20, reduces the surface loss eightfold, and simultaneously increases the tensile stress. Photothermal infrared spectroscopy and $\textit{in situ}$ X-ray photoelectron spectroscopy trace the enhancement to thermally activated silanol condensation - the conversion of surface hydroxyl terminations into siloxane bridges - and the reversibility of both quality factor and stress under controlled humidity confirms the surface-chemical origin. These results establish surface chemistry as a tunable parameter for next-generation ultracoherent nanomechanical resonators.
