201122143 六、發明說明： 【發明所屬之技術領域】 本發明是關於一種形成平滑鑽石薄膜的方法；尤其，本發明提出 一種以獨特MPJCVD系統所進行的電漿預碳化法(RR法)前處理，藉由 此系統優異的能量聚焦特性（MPJCVD)成長出一表面平滑的鑽石薄 膜’如此將可提高鑽石薄膜於半導體製程之應用並可製成光電元件。 本發明亦關係於由此製程製造出之鑽石薄膜之應用。 【先前技術】 以微波電漿化學氣相沉積法(Microwave plasma chemical vapor 鲁 deposition system，MPCVD)合成鑽石薄膜，為業界已知。此一方法主 要是將一種或多種反應氣體通入反應室中，經過頻率2.45GHz的微波 電漿解離’使其產生化學反應後’在基材/基板表面合成固態薄膜。由 於其具有(1)系統穩定、反應溫度與反應壓力較低(2)較高電漿密度與解 離率(3)不需電極且電漿層電位較低可減少製程污染(4)分子鍍層純度 高，鍍膜品質佳且製程再現性佳等優點，因此具有工業化生產能力。 但是在各種應用上’此方法仍有許多待克服的問題，如沉積速率偏低、 電漿沉積薄膜的均勻性及表面平整性，特別是電漿穩定性的問題。 第096110652號專利申請案(公開號：200839026)為發明人開發之 • 微波電漿喷射化學氣相沉積電漿系統(Microwave plasma jet ehemieal vapor d印osition system，MPJCVD;) ’此系統亦包含上述以mpcvd設 備帶來優點；在另一方面，由於MPJCVD系統是利用天線導引微波使 電聚形成於天線尖端成現出喷射狀，天線可將電漿束局限於其尖端位 置，使電漿能穩定的分佈於欲合成鑽石膜的基板上，所以微波喷射電 锻系統可具有更高的電子密度、游離率和穩定的電漿分佈以改善傳統 鐘罩式或管狀式微波電漿CVD系統中電漿功率密度過低與分佈不均之 問題。而電漿合成鑽石薄膜的表面平整性問題則使用本發明之 MPJCVD系統之電漿預碳化法(ρ.ρ·)前處理即可得到良好改善，將鑽石 膜的表面粗糙度改良提升至Ra : 8.G14肺。此等優點觸顺^所 不及。 201122143 由於鑽石具有相當南的表面能[5.3 1/〇112於(111)、9.2了/(：1112於 (100)，所以鑽石非常難以在異質基材表面上成核，如圖i所示。為了 使鑽石薄膜能夠沉積於矽基材/石夕基板上，因此目前鑽石膜的合成發展 出許多基材/基板前處理方法以提高成核密度，其中主要包括刮痕法、 種晶法、離子佈值法及偏壓輔助成核法。其中又以超音波震盪刮痕法 (ultrasonic scratching)、基材偏壓(bise)及鑽石晶種成核等三種前處^方 法對鑽石成核密度提高之效益最為顯著與穩定。 刮痕法是利用鑽石粉末懸浮液’以超音波震盪使基材/基板表面製造 刮痕，以增加成核密度。但此法容易造成基材/基板表面受損或是污染。 基材偏壓輔助成核法是利用負偏壓場成長高方向性鑽石膜，基材偏壓 輔助鑽石膜增加孕核密度之機制，其電漿組成主要為微波電漿與輝光 放電(二次電漿)兩項組成’其輝光放電會隨著鐵石核種的形成從外圍逐 ，向中心祕’ 了解轉性之後便可以得知科致成财均勻且不穩 定的問題。鑽石晶種成核法則是利用特別比例之鑽石粉懸浮液，以物 理旋轉塗佈方式將鑽石粉末均勻彼覆在基材/基板表面，造成微小的鑽 石顆粒殘留在基材/基板表面，使成長之鑽謂料在朗_石顆粒 上繼續成長，增加初始成核率，但其缺點為旋轉塗佈的過程中，殘留 之奈米鑽石粉末顆粒並不能提供一平滑基底，使得成長鑽石膜後之表 面，縫度不佳。上述方法皆有不利於工業應用上的缺點，因此，有必 要提出y觀方法以解決上述各種成長鑽石膜的基材/基板前處理所造 成的問題’並且仍能保有高的成核紐，躺可獲得表面平滑的鑽石 薄膜’如圖2所示。 【發明内容】 、，發明提ib-種成長鑽;5狀祕理方法_電賴碳化法(RR)來解 j知問題^根據本發明，電漿預碳化邮p )技術巾，是使用微波電 喷射化學氣相沉積電漿系統⑽__ plasma ^ chemical vap〇r deposition system ’ MPJCVD)系、統在鑽石職長之前先於石夕基材/基板上 預鍍上-非晶質碳薄層，以供鑽石薄膜成長於其上。 在非曰曰質碳:C )薄層製程中首先將清洗過之矽基材/基板以 5 201122143 MPJCVD系統使用C-Η電襞鑛上非晶質碳(a:c)薄層，接著再將鍍上 碳(a:C)薄層之石夕基材/基板放入特定比例的鑽石奈米粉末懸浮液内又經 物理方式，如超音波紐，使鑽石奈米晶種均勻分佈於其上，此技術 的最大優點猶處理製程巾基板絲面並未遭受到麵與汙染，仍保 有平滑之基板表誠利後續平滑鑽石薄膜之長成，大幅改善鑽石薄膜 成長時的成核不均與基板表面因前處理的破壞或污染留下的痕跡影響 薄膜整體表面的平整度。 根據本發明所提出之電漿預碳化法(P.P.)可有效將粗糙度降低，其原 因為使用MPJCVD系統所預鍍上之非晶質碳(a: c)薄層十分平坦且未 φ 對矽基板表面造成破壞’鑽石膜得以在此平坦的中介層(media la㈣上 沉積’故可合成出表面相當平滑的鑽石膜，此外，由於此非晶質碳(α : c ) 薄層與鑽石同屬碳元素材料，加上試片預鍍上碳層後有再經過奈米鑽 石粉末懸浮液超音波震盪處理，所以可將鑽石奈米晶種均勻分佈於碳 薄層上，故成長鑽石膜時很容易在此非晶質碳(a:c)薄層找到新的成 核點以利鑽石膜成長之孕核。由於上述兩點原因，所以本發明之電漿 預碳化法可以在鑽石膜之孕核階段有效地提高初始成核率並且在鑽石 膜成長階段使用適當的製程參數以提高二次成核率合成出奈米晶鑽石 膜(Nano crystalline diamond ’ NCD)，如此將可以得到一表面粗糙度極 低(Ra=8.014nm)的奈米晶鑽石膜(NCD)，而以此技術合成的NCD膜除 _ 了仍擁有一般微米晶鑽石膜(Micrometer crystalline diamond，MCD)優異 之性質外’由於其表面粗糙度遠小於微米晶鑽石膜，所以可克服^^^^ 於半導體製程因本身表面粗糙使多層材料堆疊時表面粗糙放大及附著 度不佳之限制，因此提高鑽石膜在光電半導體元件或微機電系統 〇VficiOelectiO-mechanical System，MEMS)材料上的應用發展。 爲驗證本發明所提出之電漿預碳化法(P.P.)前處理成長之表面確實 疋平;月’將使用掃描式電子顯微鏡(scanning electron micr()Se()py， 和原子力顯微鏡(atomic force microscopy，AFM)來觀察及量測奈米晶鑽 石膜之表面形貌與表面粗糙度’此外，並使用X光繞射儀(XKD)對所 成長之鑽石薄膜進行結晶分析，証實其為鑽石薄膜，而使用拉曼光譜 儀(Raman spectra)則可提供所合成的材料其鍵結結構用以判斷非晶質〖^ 6 201122143 碳(a:c)薄層的鍵結組成。 【實施方式】 所門Γ所示為本發明使用之刪㈣系、統。本發日月於是基於此系統 /ίί前處理技術·預碳化法(RR)，為形成平滑的鑽石薄 本，明首先以下列步驟形成一中介層（非晶質碳(a:c)層）： α·提供一具有一封閉空間之一反應腔體； β·將一處理氣體引入至該封閉空間中；201122143 VI. Description of the Invention: [Technical Field] The present invention relates to a method of forming a smooth diamond film; in particular, the present invention provides a plasma pre-carbonization (RR method) pretreatment by a unique MPJCVD system. By using the system's excellent energy focusing characteristics (MPJCVD) to grow a smooth surface diamond film 'this will improve the application of diamond film in semiconductor manufacturing process and can be made into photovoltaic components. The invention is also related to the use of diamond films produced by such processes. [Prior Art] A diamond film is synthesized by Microwave plasma chemical vapor deposition (MPCVD), which is known in the art. In this method, one or more reaction gases are introduced into the reaction chamber, and a solid film is synthesized on the substrate/substrate surface after dissociation by a microwave plasma having a frequency of 2.45 GHz to cause a chemical reaction. Because it has (1) system stability, low reaction temperature and low reaction pressure (2) high plasma density and dissociation rate (3) no electrode and low plasma layer potential can reduce process pollution (4) molecular coating purity High, good coating quality and good process reproducibility, so it has industrial production capacity. However, in various applications, there are still many problems to be overcome, such as low deposition rate, uniformity of plasma deposited film, and surface flatness, especially plasma stability. Patent Application No. 096110652 (Publication No.: 200839026) developed by the inventor: Microwave plasma jet ehemieal vapor osition system (MPJCVD;) 'This system also includes the above The mpcvd device brings advantages; on the other hand, since the MPJCVD system uses the antenna to guide the microwave so that the electropolymer is formed at the tip of the antenna to form a jet, the antenna can limit the plasma beam to its tip position, so that the plasma can be stabilized. Distributed on the substrate of the diamond film to be synthesized, so the microwave jet electric forging system can have higher electron density, free rate and stable plasma distribution to improve the plasma in the traditional bell-type or tubular microwave plasma CVD system. The problem of low power density and uneven distribution. The surface flatness problem of the plasma synthetic diamond film can be improved by using the plasma pre-carbonization method (ρ.ρ·) pretreatment of the MPJCVD system of the present invention, and the surface roughness of the diamond film is improved to Ra: 8. G14 lung. These advantages are not as good as they can be. 201122143 Since diamonds have a fairly south surface energy [5.3 1/〇112 at (111), 9.2/(:1112 at (100), it is very difficult for diamonds to nucleate on the surface of a heterogeneous substrate, as shown in Figure i. In order to enable the diamond film to be deposited on the ruthenium substrate/Shixi substrate, the synthesis of the diamond film has developed many substrate/substrate pretreatment methods to improve the nucleation density, including scratching, seeding, and ion. Cloth value method and bias-assisted nucleation method, in which the nucleation density of diamond is improved by three methods: ultrasonic scratching, substrate bias (bise) and diamond seed nucleation. The benefits are most significant and stable. The scratch method is to use the diamond powder suspension to make scratches on the substrate/substrate surface by ultrasonic vibration to increase the nucleation density. However, this method is likely to cause damage to the substrate/substrate surface or It is pollution. The substrate bias assisted nucleation method is to use a negative bias field to grow a high directional diamond film. The substrate bias assists the diamond film to increase the density of the nucleus. The plasma composition is mainly microwave plasma and glow discharge. (secondary plasma) two In the glow discharge, the formation of the nucleus will follow the formation of the iron core nucleus, and the central secret will understand the problem of uniformity and instability of the science. The diamond seed nucleation law uses a special proportion. Diamond powder suspension, the diamond powder is evenly coated on the substrate/substrate surface by physical spin coating, causing tiny diamond particles to remain on the substrate/substrate surface, so that the growing diamond material continues on the lang_stone particles. Growth, increase the initial nucleation rate, but its shortcoming is that during the spin coating process, the residual nano-diamond powder particles can not provide a smooth substrate, so that the surface after the diamond film is grown, the seam is not good. It is not conducive to the shortcomings of industrial applications. Therefore, it is necessary to propose a method to solve the problems caused by the substrate/substrate pretreatment of the above various growth diamond films' and still maintain a high nucleation nucleus. The diamond film 'is shown in Fig. 2. [Invention], the invention raises the ib-type growth drill; the 5-shaped secret method _ the electric aging carbonization method (RR) to solve the problem ^ according to the present invention Plasma pre-carbonization p) technical towel, is the use of microwave electrospray chemical vapor deposition plasma system (10) __ plasma ^ chemical vap〇r deposition system 'MPJCVD) system, before the diamond captain before the stone substrate / substrate A thin layer of amorphous carbon is pre-plated to allow the diamond film to grow thereon. In the non-ruthenium carbon: C) thin layer process, the cleaned ruthenium substrate/substrate is first used as a thin layer of amorphous carbon (a:c) on the C-Η Η 襞 , 5 5 5 201122143 MPJCVD system, and then Putting a thin layer of carbon (a:C) on the stone substrate/substrate into a specific proportion of the diamond nano powder suspension and physically distributing the diamond nano seed evenly in a physical manner, such as ultrasonic wave The biggest advantage of this technology is that it does not suffer from surface and contamination on the surface of the substrate of the process towel, and still maintains a smooth substrate. The success of the subsequent smooth diamond film is greatly improved, and the nucleation unevenness during the growth of the diamond film is greatly improved. The surface of the substrate affects the flatness of the overall surface of the film due to damage caused by pretreatment or traces of contamination. The plasma pre-carbonization method (PP) according to the present invention can effectively reduce the roughness because the amorphous carbon (a: c) layer pre-plated using the MPJCVD system is very flat and has no φ confrontation. The surface of the substrate causes damage. 'The diamond film can be deposited on this flat interposer (media la (4)', so that a relatively smooth diamond film can be synthesized. In addition, since this amorphous carbon (α : c ) thin layer is the same as the diamond The carbon material material, plus the pre-plated carbon layer of the test piece, is subjected to ultrasonic vibration treatment of the nanometer diamond powder suspension, so that the diamond nano seed crystal can be evenly distributed on the carbon thin layer, so the diamond film is grown very much. It is easy to find a new nucleation point in this amorphous carbon (a:c) thin layer to facilitate the growth of the diamond film. For the above two reasons, the plasma pre-carbonization method of the present invention can be used in the diamond film pregnancy. The nuclear stage effectively increases the initial nucleation rate and uses a suitable process parameter to increase the secondary nucleation rate to synthesize a nanocrystalline diamond 'NCD' during the diamond film growth stage. This will result in a surface roughness. Very low (Ra=8.014nm) Nanocrystalline diamond film (NCD), and the NCD film synthesized by this technology has the excellent properties of the general micrometer crystalline diamond (MCD), because its surface roughness is much smaller than that of the microcrystalline diamond film. Therefore, it can overcome the limitation that the surface of the semiconductor process is rough and the adhesion is poor when the multilayer process is stacked due to the surface roughness of the semiconductor process, thereby improving the diamond film in the optoelectronic semiconductor component or the microelectromechanical system (VficiOelectiO-mechanical System, MEMS) Application development on materials. In order to verify that the surface of the plasma pre-carbonization (PP) pretreatment of the present invention is grown, the surface is indeed flattened; the moon' will use a scanning electron microscope (scanning electron micr), and an atomic force microscopy (atomic force microscopy). , AFM) to observe and measure the surface morphology and surface roughness of the nanocrystalline diamond film' In addition, and use the X-ray diffractometer (XKD) to crystallize the grown diamond film to confirm that it is a diamond film, The Raman spectra can be used to provide the bonded structure of the material to determine the bond composition of the amorphous (a:c) thin layer. [Embodiment] Shown for the use of the invention (de) system, the system is based on this system / ίί pre-treatment technology · pre-carbonization (RR), in order to form a smooth diamond thin, first form an intermediary with the following steps Layer (amorphous carbon (a:c) layer): α· provides a reaction chamber having a closed space; β· introducing a process gas into the closed space;
將來自-能置源(如能量源包含一微波產生器)之能量輕合導引 至該反應腔體中； D·將-基缺位在該反應腔_且以化學氣相合成方式結合至該 基板。 詳而言之，本發卿解_石_之紐大致包括下列步驟： 1.首先，將洗淨過後之基材/基板(較佳為石夕基材)放人聰CVD系 可，並且使用C-H電漿鍍上-非晶質碳(a:c)薄層。此層 k供平/3且柔軟的基底料成長鑽石細的中介層。 此届步驟之非晶質碳(a:C)薄層與鑽石為同元a素材料，所以在 ^j鑽石膜可減少鑽石_成核的潛伏期，進而增加鑽石之初始 兩二薄層可使用拉曼光譜儀清她 所示。、^質碳的特徵峰哪撕叫和G(158(Wl)band，如圖4 會受中所用:成_^ 蓮留痕或科，而影響後續所成長之鑽石 、’又。然而，根據本發明之製程，並未在基板/基材之表 的表面Γ何痕跡或污染’所以後續長成之鑽石薄膜表面具有極為平滑 定錢上非晶質碳(α: c)薄層之石夕基材/基板放入以特 =比例所綱出之奈米齡粉耗频4_i ΐ:; 0 ^ 4層上。超a波震錢理完成後，此_基材/基板表面會_具備斤 201122143 非晶質碳(α: C )薄層以及均勻分布於其上之奈米鑽石晶種 ，所以在成 鐵石膜時很谷易在此非晶質碳(α: c )薄層找到新的成核點繼續鑽石 膜的n。最後將此0基材/基板放人⑽冗奶纟_使肖適當製程參 數來提同一次成核率，如此將可以得到一表面平滑、極低粗糙度 (Ra=8.014nm)的超奈米晶(UNCD)，即完成本發明所提出之電槳預碳化 法(P.P.)。本發明之賴舰化法(pR)主要麵触難糊則如圖5 所示。Directly coupling the energy from the source (such as the energy source comprising a microwave generator) to the reaction chamber; D·the base is absent in the reaction chamber _ and is chemically synthesized to The substrate. In detail, the present invention contains the following steps: 1. First, the substrate/substrate after cleaning (preferably the stone substrate) can be placed on the CVD system and used. CH plasma is plated with a thin layer of amorphous carbon (a: c). This layer k is a flat/3 and soft base material that grows into a thin interpenetrating layer of diamond. This step of the amorphous carbon (a:C) thin layer and the diamond is the same element a material, so the diamond film can reduce the incubation period of the diamond _ nucleation, thereby increasing the initial two or two thin layers of the diamond can be used The Raman spectrometer clears her. The characteristic peak of the carbon is called T and G(158(Wl)band, as shown in Figure 4, it will be used in the following: _^ Lotus leaves or the branch, which affects the diamond that grows later, 'again. However, according to The process of the present invention does not have any trace or contamination on the surface of the substrate/substrate surface. Therefore, the surface of the diamond film which is subsequently grown has an extremely smooth amorphous carbon (α: c) thin layer. The substrate/substrate is placed in a special ratio of nanometer-aged powder consumption frequency 4_i ΐ:; 0 ^ 4 layer. After the super-a wave shock is completed, the _substrate/substrate surface will have jin 201122143 A thin layer of amorphous carbon (α: C) and nano-diamond crystals uniformly distributed on it, so it is easy to find a new layer in this amorphous carbon (α: c) thin layer when it is a molten iron film. The nucleation point continues the n of the diamond film. Finally, the 0 substrate/substrate is placed in the (10) trousers _ to make the appropriate nucleation rate for the appropriate process parameters, so that a smooth surface and very low roughness can be obtained. Ultra-nanocrystal (UNCD) of Ra=8.014nm), that is, the electric paddle pre-carbonization method (PP) proposed by the present invention is completed. The main surface of the invention (pR) is difficult to paste as shown in Fig. 5. Show .
使用本發明所提出之電漿預碳化法(P.P.)所成長之鑽;5膜，以x光繞 射儀(XRD)來分析可驗證所成長確實為鑽石膜，並且為具有⑴、、 (220) (311)等二種晶面的多晶鑽石膜如圖6所示。並且可由掃描 子顯微鏡(SEM)之剖面圖觀察其表面雜，發現使用本發明 ^ 化法(P.P·)後，確實可以制—平滑之表面。最後細可由原子^ 鏡(AFM)來得知其表面之粗操度為Ra=8 〇14nm，如圖8所示。•’ 【圖式簡單說明】 圖1·為無前處理情況下所合成之鑽石膜示意圖。 圖2.為合成平滑之鑽石膜示意圖。 圖3.展示本發明使用之mpjcvd系統。 圖4.本發明P.R法所預鍍上之非晶質碳(〇〇:(：)薄層拉曼光譜。 圖5_本發明所提出之電漿預碳化法(pp)實驗步驟流程圖。 圖6.所合成之鑽石薄膜XRD圖。 圖7.本發明P.R法合成之SEM鑽石膜剖面圖。 圖8.所合成之鑽石薄膜AFM圖。 【主要元件符號說明】The diamond grown by the plasma pre-carbonization method (PP) proposed by the present invention; 5 film, analyzed by x-ray diffractometer (XRD), can verify that the growth is indeed a diamond film, and has (1), (220 (311) Two crystal face polycrystalline diamond films are shown in Fig. 6. Further, the surface impurity can be observed by a scanning electron microscope (SEM) sectional view, and it is found that a smooth surface can be produced by using the present invention (P.P.). Finally, the atomic mirror (AFM) can be used to know that the surface has a roughness of Ra = 8 〇 14 nm, as shown in Fig. 8. • ' [Simple description of the diagram] Figure 1 is a schematic diagram of the diamond film synthesized without pretreatment. Figure 2. Schematic representation of a synthetic smooth diamond film. Figure 3. Shows the mpjcvd system used by the present invention. Figure 4. Amorphous carbon pre-plated by the PR method of the present invention (〇〇: (:) thin layer Raman spectrum. Figure 5 - Flow chart of the experimental procedure of the plasma pre-carbonization method (pp) proposed by the present invention. Figure 6. XRD pattern of the diamond film synthesized. Figure 7. Cross-sectional view of the SEM diamond film synthesized by the PR method of the present invention. Figure 8. AFM pattern of the diamond film synthesized.