利用射頻磁控濺鍍法在具有鑽石薄膜之矽晶片上沉積氧化鋅薄膜及表面聲波之應用

Deposition of Highly C-axis Oriented ZnO Thin Films on Diamond/Si Substrates by RF Magnetron Sputter for Surface Acoustic Wave Application

王茂進(Mao-Jin Wang)

指導教授 ： 施文欽

大同大學/電機資訊學院/光電工程研究所/碩士(2007年)

摘要

近年來氧化鋅廣泛地被應用在表面聲波元件，它已經成功地被成長在quartz、Si、GaAs、sapphire基板上，其中成長sapphire基板更被廣泛的應用在高頻表面聲波元件，其主要原因為sapphire基板具有高聲速的之優點，然而由於sapphire基板價格較 Si 基板昂貴且不利於大面積化，在本研究中，我們成長ZnO在Diamond/Si上以達高頻表面聲波元件應用。
以鑽石相關材料為基底之表面聲波元件，在其元件之工作頻率已被證實其優越之特性。在本研究中，我們將探討不同型態之鑽石基板對元件波傳遞特性之影響。我們利用射頻磁控濺鍍法分別沉積ZnO薄膜於奈米鑽石（NCD）/Si與微米鑽石（MCD）/Si基板上，並製作成表面聲波元件。實驗結果顯示，其ZnO薄膜C軸優選方向之半高寬分別為0.21˚與0.23˚，薄膜表面平坦度分別為18.5 nm與9.3 nm，並利用網路分析儀量測元件之頻率響應，其IDT/ZnO/NCD/Si之第0模態之波速為5296 m/s（331 MHz），ZnO/IDT/NCD/Si之第1模態之波速為8960 m/s（448 MHz）。實驗所得結果與前人所作之理論分析結果相近。

關鍵字

氧化鋅 ； 奈米鑽石 ； 微米鑽石 ； 表面聲波 ； 濺鍍

並列摘要

Among recently developed piezoelectric thin film materials, ZnO has been considered to be very promising for fabricating thin film surface acoustic wave (SAW) devices. ZnO thin films have been deposited on quartz, Si, GaAs and sapphire substrates. In these substrates materials, sapphire is widely used for high frequency SAW device due to its high acoustic velocity. However, the sapphire substrate is more expensive than Si wafer, and it is still very difficult to grow large size of Al2O3 single crystal. In this study, we adopt the ZnO thin film on Diamond/Si substrate as a promising substrate for high-frequency SAW device.
Surface acoustic wave device built on diamond related substrates have been proven their superiority in working frequency. To evaluate the effects of diamond substrates for wave propagation, different thicknesses and types of diamond films, such as nanocrystalline diamond（NCD）and microcrystalline diamond（MCD）, are adopted in this study for comparison. The c-axis orientated ZnO films are sputtered on the NCD films and polished MCD films as the piezoelectric films. The experimental results show that the highly c-axis oriented ZnO films could be obtained. The full width at half maximum intensity（FWHM）of ZnO（002）films on NCD and MCD films obtained from the X-ray diffraction （XRD）were 0.21 ° and 0.23 °, respectively. The surface roughness of the ZnO films on NCD and MCD films was about 18.5 nm and 9.3 nm, respectively. It was found that the oth mode in the IDT/ZnO/NCD/Si structure has the velocity of 5296 m/s（331 MHz）, and the 1st mode in the ZnO/IDT/NCD/Si structure has the velocity of 8960 m/s（448 MHz）. The experimental results are in agreement with those published in the literatures.

並列關鍵字

zinc oxide ； nanocrystalline diamond ； microcrystalline diamond ； surface acoustic wave ； sputtering

參考文獻

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