本文利用單晶X切面的鈮酸鋰壓電薄膜(Single Crystal X-cut Lithium Niobate)以及二氧化矽組成複合材料實現高性能共振器，我們利用二氧化矽具備正頻率溫度係數(Temperature Coefficient of Frequency, TCf)的特性，能夠與鈮酸鋰互補，達到溫度補償效果以改善元件的溫度穩定性，並透過優化固定樑端設計，製作出高品質因數(Quality Factor，簡稱Q)的超高頻水平剪切模態之平板聲波共振器。
本研究之元件利用指叉狀電極(Inter-digital Electrodes)設計以激發出水平剪切模態，由於水平剪切模態在所選擇的X切面鈮酸鋰材料中具有高機電耦合係數的優勢，因此本文以此作為共振器的目標模態，並使用模擬軟體COMSOL進行有限元素分析法(Finite Element Method, FEM)預測設計結果，模擬出元件共振時的模態以及頻率響應。
為了實現元件，本文利用市售的單晶X切面的鈮酸鋰薄膜晶片，對其進行表面微加工製程(Surface Micromachining)技術來製作共振器元件，並根據學術界有限的資源，設計了兩套製程流程，以實現鈮酸鋰薄膜共振器以及鈮酸鋰/二氧化矽溫度補償共振器。製程流程可區分為三個階段，第一階段為黃光微影，定義指叉狀電極與蝕刻槽；第二階段為蝕刻製程，分別對硬擋層及鈮酸鋰進行乾蝕刻；第三階段為元件的釋放，方能使共振器結構懸浮。
根據本文所設計的製程製作出來的共振器量測結果在空氣中Q值最高可達到1,600，真空中最高更可達到3,900以上，而機電耦合係數(Electromechanical Coupling Coefficient, kt2)大於3.8%。此外，評量整體元件的表現的還有性能指標(Figure of Merit, FOM)，其計算方式為FOM=〖k_t〗^2×Q，本文元件FOM的最佳值為148。

This work reports a 40-MHz lithium niobate-on-oxide (LN/SiO2) micromechanical resonator which simultaneously features a compensated temperature coefficient of frequency (TCf) of -13 ppm/°C and a record high Q >3,900 in vacuum (Q >1,600 in air) for low phase noise oscillators.
A high-quality 0.7-μm X-cut LN thin film atop a 2-μm SiO2 compensation layer was used to form the body of the proposed resonator based on a quasi-fundamental shear horizontal (Q-SH0) plate wave with acoustic propagation in 170° rotated from the Y-axis.
The proposed LN-SiO2 resonator is suspended with a 5-μm narrow-width supporting beam to mitigate the acoustic energy loss to substrate, thus exhibiting a best-case Q of 3,900 in vacuum with keff2 > 3.8% (FOM = keff2×Q > 148). The closed-loop oscillator was demonstrated with a commercial phase-locked loop (Zurich HF2LI PLL) under a loop bandwidth of 90 kHz. Measured phase noise for the 40-MHz LN-SiO2 Q-SH0 wave oscillator at 1 kHz and 10 kHz offsets are -110 dBc/Hz and -123 dBc/Hz, respectively, with a minimal bias instability of only 6.2 ppb.

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