Freestanding silicon nitride (SiN) devices are central to the field of nanomechanical resonators and other technology applications such as transmission electron imaging and nanopore bioassays. Nanofabrication techniques used for fabricating these devices often lack flexibility. While photolithography requires printing of an expensive photomask for each new design iteration, electron beam lithography is slow and commands high equipment cost. Here, we demonstrate maskless rapid prototyping of freestanding SiN nanomechanical resonators fabricated by femtosecond laser ablation of a plain SiN membrane in ambient air. We fabricate microbeams with different widths from 7 to 100 μm, and we characterize their resonance frequency and mechanical quality (Q) factors. We find that membrane cracking can be avoided during fabrication by carefully engineering the etch pattern, and that laser etching has a negligible effect on built-in tensile stress. For each beam, Q-factors are measured for several eigenmodes and are found to remain high after laser etching. All beams show quality factors greater than 10⁵, while unetched plain membranes have Q > 10⁶. Possible causes for Q-factor reduction are identified, along with future process improvement directions.

中文翻译：

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无掩模飞秒激光微加工制造的高品质因数氮化硅纳米机械谐振器

独立式氮化硅 (SiN) 器件是纳米机械谐振器和其他技术应用（例如透射电子成像和纳米孔生物测定）领域的核心。用于制造这些设备的纳米制造技术通常缺乏灵活性。虽然光刻需要为每个新的设计迭代印刷昂贵的光掩模，但电子束光刻速度慢且设备成本高。在这里，我们展示了通过飞秒激光烧蚀环境空气中的普通 SiN 膜制造的独立 SiN 纳米机械谐振器的无掩模快速原型制作。我们制造宽度从 7 到 100 μ不等的微束 m，我们描述了它们的共振频率和机械质量 (Q) 因素。我们发现，通过仔细设计蚀刻图案，可以在制造过程中避免薄膜开裂，并且激光蚀刻对内置拉伸应力的影响可以忽略不计。对于每个光束，测量几个本征模的 Q 因子，发现激光蚀刻后 Q 因子仍然很高。所有光束的品质因数都大于 10 ⁵，而未蚀刻的普通膜的 Q > 10 ⁶。确定 Q 因数降低的可能原因，以及未来的工艺改进方向。