摘 要

　　隨著行動電話的普遍，無線網路與衛星傳播的發展，使得高頻元件的需求增加。擁有體積小及濾波效果佳等優點的表面聲波濾波器元件因而變的相當熱門。表面聲波濾波器元件的頻率決定於材料的表面聲波波速。鑽石擁有超過10000m/s的表面聲波波速，是所有材料中最高的。但是鑽石不具有壓電特性，必須在其表面鍍上一層壓電薄膜才能使其成為一個令人滿意的表面聲波濾波器元件。
　　有鑑於鑽石與氮化鋁的結合可達到高的操作頻率，因此成為一個新且令人注目的研究。不同從優取向的氮化鋁薄膜擁有不同的壓電特性，但其中以(002)從優取向(c軸取向)之壓電特性最佳。因此在本研究將探討製程參數對c軸取向之影響。
　　結果顯示較高的濺鍍功率與越低的氮氣流量、工作壓力、濺鍍距離和適當的溫度，越容易沈積(002)從優取向氮化鋁薄膜於鑽石基板上，乃因越高能量的濺鍍原子對形成(002)表面越有利。除此之外，由於鑽石與c軸取向的氮化鋁擁有較小的晶格不匹配使得容易形成c軸取向的沈積。
　　實驗利用此研究之最佳參數製造氮化鋁/鑽石表面聲波濾波器元件。所測得的中心頻率約293.75MHz，對應之波速值為9400m/s，由此可得知鑽石有助於提升表面聲波濾波器元件特性，且氮化鋁機電耦合係數為0.35％.

Abstract

　　The demand for high-frequency devices has raised due to the increase spread of mobile telephones, satellite broadcasting and wireless local area network system. SAW devices have become popular due to its advantages of small size and fine filtering character.
　　The center frequency of the SAW filters is determined by SAW velocity of material. Diamond has the highest SAW among all substances and its value more than 10000m/s. However, diamond is not piezoelectric, its high acoustic propagation makes it a desirable substrate for SAW devices when coupled with piezoelectric thin films.
　　The use of AlN in combination with diamond is new and attractive for operating at very high frequencies. AlN thin films with various preferred orientation show different piezoelectric behavior, and (002) preferred orientation (c-axis) is shown to be better. So the relationship between c-axis orientation and process parameters will be investigated in this study.
　　The results show that higher RF power and lower N2 gas flow rate, working pressure and sputtering distance and suitable substrate temperature , is easy to form the (002) preferential orientation of AlN films deposited on diamond substrate, which referred to the adatoms with a higher energy are energetically favorable for the formation of (002) surface planes. Besides, It is beneficial to deposit C-axis AlN thin film on diamond substrate due to a smaller lattice mismatch.
　　We made AlN/diamond SAW device by optimizing sputtering conditions in this study . The center frequency of this SAW device is about 293.75MHz corresponding to 9400m/s velocity, which could reveal diamond promote the character of SAW and the К2 of AlN was 0.35%.

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