利用射頻磁控濺鍍法沈積氮化鋁薄膜並應用於表面聲波元件

Fabrication of AlN thin films by RF magnetron sputtering method and their surface acoustic wave applications

鄒志雄(Zhi-xiong Zou)

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

目前通訊元件有朝著高頻化的發展趨勢，而高頻表面聲波元件須具有高波速，高機電耦合係數，低插入損失等特性，我們可以透過不同的壓電薄膜和基底材料互相組合的表面聲波元件來達到這些特性。其中氮化鋁(AlN)薄膜擁有良好的壓電特性、高表面聲波波速(5600～6000 m/s)，加上能與半導體製程相結合，所以我們選擇AlN為SAW元件的壓電特性的研究材料。
本論文是利用射頻磁控濺鍍法來沈積氮化鋁薄膜於SiO2/Si和Sapphire基板上，我們也順利找到當射頻功率(RF power)為350 W、氮氣比例濃度(N2 concentration rate)在40 ％、製程壓力(working pressure)在4 mtorr、基板溫度(substrate temperature)為200 ℃時可得到具有高C軸優選取向的氮化鋁薄膜的沈積條件。
之後也在SiO2/Si和Sapphire基板兩種結構上成功地製作表面聲波元件，並利用網路分析儀得到中心頻率分別為249.78 MHz和279.45 MHz，證實氮化鋁薄膜其良好的壓電特性。

關鍵字

氮化鋁 ； 射頻磁控濺鍍 ； 表面聲波

並列摘要

Recently, most communication devices which are developing toward high frequency have become important. The high frequency surface acoustic wave (SAW) devices are one of them. High frequency SAW devices must have some properties such as large eletro-mechanical coupling coefficient, low insertion loss and high acoustic velocity. We can use different piezoelectric thin films and substrate material to get these properties.
Because of its excellent piezoelectric property and high acoustic frequency(5600~6000 m/s), the c-axis oriented aluminum nitride(AlN) thin film has received great interest. So we choose AlN thin film as our research material in this thesis.
The high c-axis oriented AlN thin films were successfully deposited on SiO2/Si and sapphire substrates by RF reactive magnetron sputtering method. We also fabricated SAW device on these substrates and measured center frequency of SiO2/Si and sapphire substrates, 249.78 MHz and 279.45 MHz, by network analyzer. We prove that AlN thin film has great piezoelectric property.

並列關鍵字

AlN ； surface acoustic wave ； RF sputtering

參考文獻

17. 張弘學, ”低溫濺鍍氮化鋁薄膜之研究”,國立台灣科技大學材料科技研究所, 2004

21. 徐國洲,“在不同基板溫度下以磁控濺鍍法成長氮化鎵薄膜之研究,”國立中山大學物理學系研究所”, 1999

1. Colin K. Campbell, “Surface acoustic wave devices for mobile and wireless communications,” 1998

2. Ju-Won Soh and Won-Jong Lee, “SAW characteristics of AlN films deposited on various substrates using ECR plasma enhanced CVD and reactive RF sputtering,” IEEE Ultrasonics Symposium, pp. 299-302, 1996

3. Xianfeng Ni, Liping Zhu, Zhizhen Ye, Zhe Zhao, Haiping Tang, Wei Hong, Binghui Zhao, “Growth and characterization of GaN films on Si(111) substrate using high-temperature AlN buffer layer,” Surface & Coating Technology, vol. 198, pp. 350-353, 2004