201110340 六、發明說明： 【發明所屬之技術領域】 本發明係有關於一種複合表面聲波基板’其特別有關於一種 由(100)面氮化鋁薄膜層構成之複合表面聲波基板，使其具有水平 男向模態。 【先前技術】 表面聲波(surface acoustic wave，SAW)元件是在壓電基板或壓 電薄膜上製作指叉式電極(IDTs，interdigital transducer)。當輸入端 的IDT加上父流訊號後，在兩電極之間會產生交變電場，電場下 方的壓電體因逆壓電效應而產生應變(Strain)，進而激發出表面聲 波，經由壓電材料表面傳遞，再由輸出端IDTs的正壓電效應將聲 波訊號轉為電氣訊號輸出。隨著各種壓電材料以及不同形式之交 鲁指叉電極相關研究陸續發展，表面聲波元件更被廣泛的應用以作 為濾波器(filter)、共振器(resonator)、延遲線㈣及感測器 (sensor)等。 -般而言’表面聲波元件是直接於壓電基板，如石英(职㈣、 銳酸鋰(LiNb03)、鈕酸鋰(LiTa〇3)等上製作指叉式電極而激發表面 聲波。然而，在高頻的設計要求下，若單純利用縮小指叉式電極 線I及改變壓電基板材料來達到高頻元件的方法無法達到要求。 近年來’為了提絲©聲波元件之操作鮮，在不同基板材 201110340 料上沉積>1電薄膜，形成複合表面聲波基板之結構已被廣泛使 用。複合表面聲波基板結構的優點在於，藉由不同的基底材料與 壓電薄膜的搭配’可同時提高表面聲波波速以及機電耦合係數， 另外’可在此種複合基板上製作不同方向指叉式電極用以激發不 同模態’使元件更能符合設計需求。 氮化銘壓電薄膜層因具有高聲波波速，因此被廣泛地應用在 表面聲波元件上。傳統上，由於氮化鋁壓電薄膜層在(〇〇2)面具有 • 最低的表面自由能，因此，氮化鋁壓電薄膜層通常是以c軸垂直 基板之(002)面所呈現，而(〇〇2)面氮化鋁薄膜不論指叉式電極方 向，其激發的表面聲波皆為雷利模態。 有鑑於此’本發明提出一種具有水平剪向模態之氮化鋁薄膜 形成之表面聲波複合基板，當波傳方向沿著γ，可產生一複數個 水平剪向模態；用以實現一種具有水平剪向模態之氮化鋁薄膜形 成之表面聲波複合基板。 【發明内容】 鑑於以上習知技術之問題’本發明提供一種具有水平剪向模 態之氮化鋁薄膜形成之表面聲波複合基板，利用化學氣相沈積法 或物理氣相沈積法在承載基板上成長具(1〇〇)面之氮化鋁壓電薄膜 廣之壓電薄膜，可廣泛應用於不同的聲波元件。 為達上述之主要目的，本發明提供一種具有水平剪向模態之 氮化鋁薄膜形成之表面聲波複合基板，其包含一承載基板;一氮化 201110340 鋁壓電薄膜層；一指叉式電極。 根據本發明之-特徵，該承載基板係選自石夕基板、二氧化石夕 土板,_、舰鐘、壓電基板、鑽石基板、坡璃基板、化合 物基板及陶瓷基板之一。 、、根據本發明之-觀，魏化罐電_層之厚度與表面聲 波波長比為〇.1至丄5。201110340 VI. Description of the Invention: [Technical Field] The present invention relates to a composite surface acoustic wave substrate which is particularly related to a composite surface acoustic wave substrate composed of a (100) plane aluminum nitride thin film layer, which has a level Male to modal. [Prior Art] A surface acoustic wave (SAW) element is an interdigital transducer (IDTs) formed on a piezoelectric substrate or a piezoelectric film. When the IDT of the input terminal is added with the parent flow signal, an alternating electric field is generated between the two electrodes, and the piezoelectric body under the electric field is strained by the inverse piezoelectric effect, thereby exciting the surface acoustic wave, and the piezoelectric wave is excited. The surface of the material is transferred, and then the positive piezoelectric effect of the output terminal IDTs converts the acoustic signal into an electrical signal output. With the development of various piezoelectric materials and different forms of cross-finger electrodes, surface acoustic wave components are widely used as filters, resonators, delay lines (four) and sensors ( Sensor) and so on. In general, the surface acoustic wave element excites the surface acoustic wave directly on the piezoelectric substrate, such as quartz (Hi), lithium niobate (LiNb03), lithium nitrite (LiTa〇3), etc., to excite the surface acoustic wave. However, Under the design requirements of high frequency, the method of reducing the interdigitated electrode line I and changing the piezoelectric substrate material to achieve high frequency components cannot meet the requirements. In recent years, the operation of the acoustic component is different. The substrate 10110340 is deposited on the material to form a composite surface acoustic wave substrate. The structure of the composite surface acoustic wave substrate has the advantage that the surface of the composite substrate can be simultaneously improved by the combination of different substrate materials and piezoelectric films. Acoustic wave velocity and electromechanical coupling coefficient, and 'can make different directions on the composite substrate, the interdigitated electrode is used to excite different modes' to make the component more in line with the design requirements. Nitriding film has high acoustic wave velocity Therefore, it is widely used in surface acoustic wave elements. Traditionally, since the aluminum nitride piezoelectric film layer has the lowest surface free energy on the (〇〇2) plane, The aluminum nitride piezoelectric film layer is usually represented by the (002) plane of the c-axis vertical substrate, and the (〇〇2) surface aluminum nitride film is excited by the surface of the fork electrode. In view of the above, the present invention proposes a surface acoustic wave composite substrate formed by an aluminum nitride film having a horizontal shear mode, and when the wave direction is along γ, a plurality of horizontal shear modes can be generated; A surface acoustic wave composite substrate formed by an aluminum nitride film having a horizontal shearing mode is realized. SUMMARY OF THE INVENTION In view of the above problems of the prior art, the present invention provides a surface formed by an aluminum nitride film having a horizontal shear mode. The acoustic wave composite substrate can be grown on a carrier substrate by a chemical vapor deposition method or a physical vapor deposition method to form a piezoelectric film having a (1 〇〇) surface of an aluminum nitride piezoelectric film, which can be widely applied to different acoustic wave elements. In order to achieve the above main object, the present invention provides a surface acoustic wave composite substrate formed by an aluminum nitride film having a horizontal shearing mode, comprising a carrier substrate; a nitrided 201110340 aluminum piezoelectric film layer According to the feature of the present invention, the carrier substrate is selected from the group consisting of a stone substrate, a silica dioxide earth plate, a ship clock, a piezoelectric substrate, a diamond substrate, a glass substrate, a compound substrate, and a ceramic. One of the substrates, according to the present invention, the thickness of the thickness of the layer of the Weihua tank and the surface acoustic wave is 〇.1 to 丄5.
根據本發明之—特徵，該複合基板之波傳方向沿著γ方向可 產生-複數個水平剪賴態，射該複數個水平剪向模態更包含 一第-水平剪向模態、—第二水平剪向模態、—第三水平剪向模 態以及一第四水平剪向模態等。 根據本發明之一特徵，該一複數個水平剪向模態之最佳表面 聲波波速為3,000 rn/s至12,350 m/s。 根據本發明之一特徵，該一複數個水平剪向模態之最佳機電 耦合係數為0.3%至1.27%。 為讓本發明之上述和其他目的、特徵、和優點能更明顯易懂， 下文特舉數個較佳實施例，並配合所附圖式，作詳細說明如下。 【實施方式】 雖然本發明可表現為不同形式之實施例，但附圖所示者及於 下文中說明者係為本發明可之較佳實施例，並請了解本文所揭示 者係考量為本發明之一範例，且並非意圖用以將本發明限制於圖 示及/或所描述之特定實施例中。 201110340 現明參考第1圖，其顯示根據本發明之實施例之具有水平剪 向㈣之氮化紹薄膜形成之表面聲波複合基板100結構示意圖。 其至少包含-承載基板12〇以及-氮化織電_層11G。該承載 基板12G可選擇魏板、二氧切基板、组酸、鈮義、壓電 基板、鑽石基板、玻璃基板、化合物基板及陶究基板。在該承載 基板120上以射頻濺鍍(RF Spmter)方式，形成氛化紹壓電薄膜層 Π0，且其晶相結構可選擇為⑽)面、（2〇〇)面或()面該氣化 •銘壓電薄膜層之厚度與表面聲波波長比為〇1至15之間。 在該氮化!S壓電細層11G之製程係選用物理氣相沈積法， 包含熱蒸錢法、電子束法與賤鑛法。在本發明中，該氮化铭壓電 薄膜層110之製程較佳係以射頻磁控濺鐘法。錢錄乾材為四英 吋、純度99.999%的紹㉟，同時使用純度為99 995%的氮氣㈣和 純度為99.999%喊氣(Ar)作為反應氣體。在該氮化紹壓電薄膜層 110之材料上’係以成長(100)面之氮化紹壓電薄膜層。若需成長 鼸（1〇〇)面之氮化紹壓電薄膜層，則該製程條件為壓力為卜1〇 m torr，射頻辨為觸〜咖w，氣體流#為5〜12s_。冑注意的是， 該氮化織電薄臈層1H)係為具有非中心對稱之六角晶系，故具 有壓電特性。 在分析複合基板之水平剪向模態波速與壓電耦合係數，必須 先從壓電聲波理論與壓電材料之剛性係數矩陣(祕顧matrix)、麼 電係數矩陣(piezoelectric matrix)、介電常數矩陣加㈤出吻娜㈣ 推導出Christoifel方程式，利用Chris爾d方程式即可解決壓電材 201110340 料中的波侧題；_波时程式配合適切的邊界條件，將可求 得不同邊界條件下的波傳特性。自由表面與具有一指叉式電極川 於氮化紹壓電薄膜層110上的表面聲波波速，可以用來求出機電 耦合係數(electromechanical coupUng fact〇r)，以 κ2表示。此耦合係 數為機械(彈性)能與電能之間能量轉換效率的指標，定義如下：機 電耦合係數 K2 =2-^-Vm ▲ vm 其中Vf為自由表面之表面聲波波速，、為有指叉式電極 於氮化!呂壓電薄膜層11〇上之表面聲波波速。該指叉式電極山 之材料可使脑、銘、鎢、鈾、銅、金、鉻、織銅氧⑽⑺)或 氧化銦錫(ITO)所組成族群中之一種材料實現。 現請參考第2圖，其顯示將晶相結構為(1〇〇)面之氮化鋁壓電 薄膜層沉積在承載基板12〇上，再將指叉式電極ln製作在晶相 φ 結構為(100)面之氮化鋁壓電薄膜層上，當承載基板120為鑽石基 板時之水平剪向模態波速與晶相結構為(丨〇〇)面之氮化鋁壓電薄膜 層之厚度與表面聲波波長比之關係圖。該複合基板之波傳方向沿 著Y方向可產生一複數個水平剪向模態，其中該複數個水平剪向 模態更包含一第一水平剪向模態、一第二水平剪向模態、一第三 水平剪向模態以及一第四水平剪向模態。該複數個水平剪向模態 之最佳表面聲波波速為5,000 m/s至12,350 m/s。該圖2顯示在晶 相結構為(励)面之氮化銘壓電薄膜層之厚度與表面聲波波長比為 201110340 0.〇4 a^· ’該第—水平剪向模態之最絲面聲波波速為η,奶m/s， 隨者晶相結構為(100)面之氮化紹壓電薄膜層之厚度與表面聲波波 長比的增加，表面聲波波速收斂至2,67()1^ ;當晶相結構為(勘) 面之氮化紹壓電薄膜層之厚度與表面聲波波長比為〇 ι〜〇 ΐ5間， 開始產生該第二水平剪向模態，第二水平剪向鋪之最大表面聲 波波速為I2,323 m/s ’隨著晶相結構為(1〇〇)面之氮化紹壓電薄膜 層之厚度絲面聲波波長比的增加，表面聲波波速钱至2,711 m/s ° «亥複s基板更包含一金屬薄膜層（未顯示於圖中），設置於該 鑽石薄膜層與氮化銘壓電薄膜之間。該金屬細層之材料係使用 鉬、鋁、鎢、鉑、銅、金、鉻、釔鋇銅氧(YBCO)輿氧化錮錫(ITO) 所組成族群中之一種材料。 上述之揭示係將該指又式電極設置於該氮化鋁壓電薄膜之 上…丨而品/主忍疋，其中s亥指叉式電極亦可以設置於該鑽石薄膜 層與氮化鋁壓電薄膜之間（未顯示於圖中）。此時，該複合基板更 包含-金屬薄膜層’設置於該氮德壓電細上（未顯示於圖 中）。該指叉式電極之材料係使用鉬、鋁、鎢、鉑、銅、金、鉻、 釔鋇銅氧(YBCO)與氧化銦錫(ITO)所組成族群中之一種材料。且該 金屬薄膜層之材料係使用鉬、鋁、鎮、鈾、銅、金、鉻、紀鋇銅 氧(YBCO)與氧化銦錫(ΙΤ〇)所組成族群中之一種材料。 現請參考第3圖，其顯示將晶相結構為(1〇〇)面之氮化鋁壓電 薄膜層沉積在承載基板120上，再將指叉式電極U1製作在晶相 201110340 結構為⑽)面之氮化雜電薄膜層上，當承裁基板m為鑽石基 板時之水平剪向模態機電轉合係數與晶相結構物_之氮化叙 壓電薄膜層之厚度與表面聲波波長比之關係圖。該複合基板之波 傳方向沿著γ方向可產生—複數财平料鶴，其巾該複數個 水平剪向模較包含—第—水平剪向模態、—第二水平剪向模 態、-第三水平剪向觀以及—細水平剪向麵。該第一水平 剪向模態之最佳機雜合係數為咖至127%，該第二水平剪向 模態之最佳機電給係數輕2%至α5%。該圖3顯示在晶相結構 為(100)面之氮化铭壓電薄膜層之厚度與表面聲波波長比為咖 時，該第一水平剪向模態有最大機電麵合雜I.274%。在晶相結 構為(10G)面之氮化|g壓電薄膜層之厚度與表面聲波波長比為 〇.7012時，該第二水平剪向模態有最大機電㉝合係數G.4608。/。。 由上述結果可知，若晶相結構為(1〇〇)面氮化銘壓電薄膜層所 構成之複合基板，不論承載基板的種類，皆可產生複數個水平剪 向模態，可以符合不同聲波元件的應用。 雖然本發明已赠述較佳實施觸示，然其並義以限定本 發明，任何熟習此技藝者，在*脫離本發明之精神和範圍内，當 可作各種之更動與修改。如上述的解釋，都可以作各型式的修正 與變化’而不會破壞此發明的精神。因此本發明德護範圍當視 後附之申請專利範圍所界定者為準。 201110340 【圖式簡單說明】 為了讓本發明之上述和其他目的、特徵、和優職更明顯， 下文特舉本發明較佳實闕，並配合所關示，作詳細說明如下： 第1圖顯示為具有水平剪向模態之⑽)面氮化_膜形成之表 面聲波複合基板結構示意圖； 第2圖顯示為當承載基板為鑽石基板時之水平剪向模態波逮與 晶相結構為⑽)面之氮化罐電薄膜層之厚度與表面聲波波長 比之關係圖； 第^圖顯示為當承载基板為鑽石基板時之水平f向模態機電轉 合係數與晶減構為(_面之氮化織電薄崎之厚度與表面 聲波波長比之關係圖； 【主要元件符號說明】 100具有水平剪向模態之氮化_卿成之表面聲波複合基板 110氮化鋁壓電薄臈層 111指又式電極 120承載基板According to the features of the present invention, the wave propagation direction of the composite substrate can generate a plurality of horizontal shearing states along the γ direction, and the plurality of horizontal shearing modes further comprise a first-horizontal shearing mode, The two horizontal shearing modes, the third horizontal shearing mode, and the fourth horizontal shearing mode. According to a feature of the invention, the optimum surface acoustic wave velocity of the plurality of horizontal shear modes is from 3,000 rn/s to 12,350 m/s. According to a feature of the invention, the optimum electromechanical coupling coefficient of the plurality of horizontal shear modes is from 0.3% to 1.27%. The above and other objects, features, and advantages of the present invention will become more apparent and understood. The present invention may be embodied in various forms, and the embodiments shown in the drawings and the following description are preferred embodiments of the present invention. The invention is not intended to limit the invention to the particular embodiments illustrated and/or described. 201110340 Referring now to Figure 1, there is shown a schematic structural view of a surface acoustic wave composite substrate 100 formed of a nitrided film having a horizontal shear direction (IV) according to an embodiment of the present invention. It comprises at least a carrier substrate 12 and a nitrided dielectric layer 11G. The carrier substrate 12G may be selected from a Wei plate, a dioxo-substrate, a group acid, a piezoelectric substrate, a piezoelectric substrate, a diamond substrate, a glass substrate, a compound substrate, and a ceramic substrate. The piezoelectric film layer Π0 is formed on the carrier substrate 120 by RF sputtering, and the crystal phase structure can be selected from (10)) plane, (2 〇〇) plane or () plane. The thickness of the piezoelectric film layer and the surface acoustic wave wavelength are between 〇1 and 15. In the process of the nitriding!S piezoelectric fine layer 11G, a physical vapor deposition method is selected, which includes a hot steaming method, an electron beam method, and a bismuth ore method. In the present invention, the process of the nitriding piezoelectric film layer 110 is preferably a radio frequency magnetron sputtering method. Qianlu dry material is a four-inch, purity 99.999% Shun 35, while using a purity of 99 995% nitrogen (four) and a purity of 99.999% shouting (Ar) as a reaction gas. On the material of the nitrided piezoelectric film layer 110, a piezoelectric film layer of a (100) plane is grown. If it is necessary to grow the 压电(1〇〇) surface of the nitride film layer, the process conditions are pressure 1 〇 m torr, radio frequency identification is touch ~ coffee w, gas flow # is 5~12 s_. It is to be noted that the nitrided woven thin layer 1H) has a non-central symmetry hexagonal crystal system and thus has piezoelectric characteristics. In the analysis of the horizontal shear mode wave velocity and piezoelectric coupling coefficient of the composite substrate, the piezoelectric acoustic wave theory and the piezoelectric material stiffness coefficient matrix (the matrix), the piezoelectric matrix, and the dielectric constant must be used. Matrix plus (5) Out of the kiss (4) Deriving the Christoifel equation, using the Chris d equation to solve the wave side problem in the piezoelectric material 201110340; _ wave time program with appropriate cutting boundary conditions, can be obtained under different boundary conditions Wave transmission characteristics. The free surface and the surface acoustic wave velocity on the piezoelectric film layer 110 having a finger-fork electrode can be used to find the electromechanical coupling coefficient (electromechanical coupUng fact〇r), expressed as κ2. This coupling coefficient is an index of the energy conversion efficiency between mechanical (elastic) energy and electrical energy, and is defined as follows: electromechanical coupling coefficient K2 = 2-^-Vm ▲ vm where Vf is the surface acoustic wave velocity of the free surface, and is an interdigitated The surface acoustic wave velocity of the electrode on the nitriding film layer 11〇. The material of the interdigitated electrode mountain can be realized by one of a group consisting of brain, inscription, tungsten, uranium, copper, gold, chromium, woven copper oxide (10) (7), or indium tin oxide (ITO). Referring now to FIG. 2, the aluminum nitride piezoelectric film layer having a (1 〇〇) crystal phase structure is deposited on the carrier substrate 12, and the interdigitated electrode ln is formed in the crystal phase φ structure. The thickness of the horizontal shear-mode modal wave velocity of the (100)-faced aluminum nitride piezoelectric film layer and the thickness of the aluminum nitride piezoelectric film layer whose crystal phase structure is the (丨〇〇) plane when the carrier substrate 120 is a diamond substrate A plot of the ratio of surface acoustic wave wavelengths. The wave direction of the composite substrate may generate a plurality of horizontal shear modes along the Y direction, wherein the plurality of horizontal shear modes further comprise a first horizontal shear mode and a second horizontal shear mode a third horizontal shearing mode and a fourth horizontal shearing mode. The optimum surface acoustic wave velocity of the plurality of horizontal shear modes is 5,000 m/s to 12,350 m/s. Figure 2 shows that the thickness of the nitriding piezoelectric film layer with the crystal phase structure is (excited) surface and the surface acoustic wave wavelength ratio is 201110340. 〇4 a^· 'The most silky surface of the first horizontal shear mode The sonic wave velocity is η, milk m/s, and the crystal phase structure is the (100) plane of the nitride film thickness and the surface acoustic wave wavelength ratio increases, the surface acoustic wave velocity converges to 2,67 () 1 ^ When the crystal phase structure is (the exploration surface), the thickness of the piezoelectric film layer and the surface acoustic wave wavelength ratio are between 〇ι and 〇ΐ5, the second horizontal shear mode is started, and the second horizontal shearing is started. The maximum surface acoustic wave velocity is I2, 323 m / s 'As the crystal phase structure is (1 〇〇) surface of the nitrided thin film layer thickness of the silk surface acoustic wave wavelength ratio increases, the surface acoustic wave wave speed to 2,711 m / s ° «Hai Fu s substrate further contains a metal film layer (not shown in the figure), placed between the diamond film layer and the nitride film. The material of the fine metal layer is one of a group consisting of molybdenum, aluminum, tungsten, platinum, copper, gold, chromium, beryllium copper oxide (YBCO) and antimony tin oxide (ITO). The above disclosure is that the finger-type electrode is disposed on the aluminum nitride piezoelectric film, and the sigma-fork electrode can also be disposed on the diamond film layer and the aluminum nitride pressure. Between electric films (not shown). At this time, the composite substrate further includes a -metal thin film layer 'on which is disposed on the Nitode piezoelectric thin (not shown). The material of the interdigitated electrode is one of a group consisting of molybdenum, aluminum, tungsten, platinum, copper, gold, chromium, beryllium copper oxide (YBCO) and indium tin oxide (ITO). And the material of the metal thin film layer is one of a group consisting of molybdenum, aluminum, town, uranium, copper, gold, chromium, yttrium copper oxide (YBCO) and indium tin oxide (yttrium). Referring now to FIG. 3, the aluminum nitride piezoelectric film layer having a (1 〇〇) crystal phase structure is deposited on the carrier substrate 120, and the interdigitated electrode U1 is formed in the crystal phase 201110340. On the surface of the nitrided film, when the substrate m is a diamond substrate, the horizontal shear mode electromechanical coupling coefficient and the crystal phase structure_the thickness of the piezoelectric film layer and the surface acoustic wave wavelength Compared to the map. The wave direction of the composite substrate can be generated along the γ direction - a plurality of financial flat cranes, the plurality of horizontal shearing modes of the towel are more than - the first horizontal shearing mode, the second horizontal shearing mode, The third horizontal shearing view and the fine horizontal shearing surface. The optimum machine hybrid coefficient of the first horizontal shear mode is 127%, and the best electromechanical coefficient of the second horizontal shear mode is 2% to α5%. FIG. 3 shows that when the thickness of the nitride film layer of the (100) plane having a crystal phase structure and the surface acoustic wave wavelength ratio are coffee, the first horizontal shear mode has a maximum electromechanical surface I.274%. . When the ratio of the thickness of the nitride film of the (10G) plane to the surface acoustic wave is 〇.7012, the second horizontal shear mode has a maximum electromechanical 33-combination coefficient G.4608. /. . It can be seen from the above results that if the crystal phase structure is a composite substrate composed of a (1 〇〇) plane nitride film layer, a plurality of horizontal shear modes can be generated regardless of the type of the carrier substrate, which can conform to different sound waves. Application of components. While the invention has been described with reference to the preferred embodiments of the invention, the invention may be modified and modified in the spirit and scope of the invention. As explained above, various modifications and variations can be made without detracting from the spirit of the invention. Therefore, the scope of the invention is defined by the scope of the appended claims. BRIEF DESCRIPTION OF THE DRAWINGS In order to make the above and other objects, features and advantages of the present invention more comprehensible, the present invention will be described in the following. FIG. 2 is a schematic diagram showing the structure of a surface acoustic wave composite substrate formed by a (10) plane nitrided film having a horizontal shear mode; FIG. 2 is a horizontal shear mode wave arrest and a crystal phase structure when the carrier substrate is a diamond substrate (10) The relationship between the thickness of the thin film of the nitrided can and the wavelength of the surface acoustic wave; the second figure shows the horizontal f-mode electromechanical coupling coefficient and the crystal subtractive structure when the carrier substrate is a diamond substrate (_face) The relationship between the thickness of the nitrided ray and the surface acoustic wave wavelength; [Major component symbol description] 100 has a horizontal shear mode nitridation _ Qingcheng's surface acoustic wave composite substrate 110 aluminum nitride piezoelectric thin 臈Layer 111 refers to a parallel electrode 120 carrying substrate