微機械電容式碰撞共振器傳感結構間隙窄化技術

Gap Narrowing for Capacitively-Transduced Micromechanical Vibro-Impact Resonators

易昀(Yun Yi)

指導教授 ： 李尉彰

國立臺灣大學/工學院/應用力學研究所/碩士(2021年)

https://doi.org/10.6342/NTU202101925

摘要

微機電元件結合機械與電子元件，擁有多種幾何形狀結構設計，及仍能維持電性特徵的獨特功能，在市場中獨具優勢。當中，射頻元件適用於移動通訊產品內，非常具有發展潛能。其中，針對射頻開關元件，藉由其大幅改善能源損耗、低介入損失及隔絕性較佳的表現，相較電子式開關有其優勢。而共振式開關更藉由共振放大位移原理，相較傳統開關，藉由期較小的驅動電壓與較大的位移，提供射頻開關一有效提高壽命之設計，加大其元件優勢。然而，共振式元件受到半導體平面製程的限制，仍未克服可靠度問題，而近期研究亦尚未有一完善解決方法。
故本論文透過絕緣體上覆矽晶圓製程，設計雙穩態彎曲樑設計之輸出電極，以設計雙穩態彎曲樑在第一穩態中，克服微影及蝕刻製程之線寬限制。在結構釋放後，驅動雙穩態彎曲樑進入第二穩態中，完成一可成功縮小輸出電極與摺疊樑梳狀共振器之間隙距離，並降低進入碰撞操作模式之驅動電壓的共振器。此外，亦建立一數學模型，由量測結果反推得元件電性上之相應參數，以及輸出電極與共振器之間隙距離與摺疊樑梳狀共振器之梳狀結構間隙等結構特徵。藉由此模型，可在非破壞式量測下得到元件之特性。
經由實驗驗證，本論文設計之共振開關，可以有效減少26%間隙距離，並降低44%驅動電壓，以提升共振開關之靈敏度。而數學模型的精確度亦透過掃描式電子顯微鏡量測，驗證此結構之間隙可透過雙穩態彎曲樑有效減少。

關鍵字

間隙窄化 ； 雙穩態 ； 摺疊樑梳狀共振器

並列摘要

Nowadays, microelectromechanical systems (MEMS) are one of the fast-growing fields. However, low reliability is one of the main challenges in this field, including both electrical and mechanical domains. The intention of this thesis is to presents an innovative way to reduce the gap distance of a resoswitch, further reduce the actuate voltage and enhance its sensitivity and reliability.
In general, resoswitch consists of the output electrode and the resonator. The device used in this work is manufactured by a typical SOI process. With traditional resoswitch, the gap distance between the output electrode and the resonator was decided by fabrication limits. However, by special design bistable output electrode, with actuaction after fabrication, can easily break through the limitations. In addition, a mathematical model was developed to characterize the device. Experiments were performed to check the validation of the model. The foundation and the features of the physical model are also explained in detail.
In conclusion, the results suggest that the special design bistable output electrode can effectively reduce the gap distance and also reduce the driving voltage. The senisitivity enhancement is significant. The accuracy of the mathematical model is verified, providing a non-destructive way to understand the mechanical and electrical characteristics of the resoswitchs.

並列關鍵字

Gap narrowing ； Bistable ； Comb-drive resonator

參考文獻

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