200805415 九、發明說明： 【發明所屬之技術領域】 本發明係涉及一種場發射陰極及其製造方法， 其涉及-種由奈米碳管陣列形成的場發射 製造方法。 ,、 【先前技術】 ， 奈米碳管係九十年代初發現的—種新型 ㈣良的综合力學性能’如高彈性; 置、⑽氏^和低密度，以及優異的電學性能、麵 學性能和㈣雜。隨著Μ料猶方式的變化、，、、 現:f屬性或半導體性質。由於奈米唆 &具有理想的-維結構以及在力學、 域優良的性質，其在材料科學、化學、物理學 ιί: 貝 =已展現出廣闊的應用前景，而形成= ==二列因其中的奈米碳管排列整二 示裝置的場發射=發射顯示技射以作爲場發射 古j 官陣列形成場發射陰極的方法主 有兩種，即··機械法及 ^ 主： 長出奈米碳管；將生長出法。機械法係預先」 成水溶膠體；長時間存放=米碳管分離、純化蒯 同的柱高位置，溶膠體後’按水溶… 需的原液加入去離; 奈米碳管組裝於潔淨的金屬基底表面從而形： 200805415 射陰極。惟，該方法 並製成水、容#還：長碳管純化、分離 亚1成水4，還需保存一個月左右，耗時較長，不 利於實際生産應用。 原:立生長法係藉由化學氣相沈積（⑶ ::=sltlon，CVD)原理直接於基底上生長奈 屬Γ二q 基底上預先形成奈米尺度的過渡金 屬或者，、減物作__，在相對低的 ，：製備奈米後管陣列從而形成場發射陰極:其 = 、二氧切或者金屬封料。當基底 U金屬材_，金屬材料的種類選擇應避免使該金 =響=氣相沈積的生長環境、或者與催化劑 形成5金、或者因其自身具有催化作用而強列分解碳 =3 ’故而可作爲基底的金屬材_議 U㈣科上’從而限制其廣泛應用。 石夕同上述方法形成的場發射陰極主要包括 夕、一乳化矽或金屬的基底、形成於基底上的全屬電 極以及形成於金屬電極上的 &上的金屬電 用石夕或者二氧化石夕材料時，=石=車列，當基底選 較差，會導致形成的場發射陰極上產 同一電極上各處的電位不相、=生電何積累以及 原位生長法生長條件的限制選用：時。：’當基底因 耐酸域的腐錄韓點較低 、’由純材料不 場發射裝置的微加I减不 ’銘基底與三極型 射陰極的下面沒㈣或:氧化二發 200805415 場發射裝置解析度較低且無法 使用該場發射陰極的 製成定址的陣列。 種克服以上缺點的場發射 有鑒於此，確有必要提供一 陰極及其製造方法。 【發明内容】BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a field emission cathode and a method of fabricating the same, which relate to a field emission manufacturing method formed of an array of carbon nanotubes. , [Prior Art], the carbon nanotubes were discovered in the early 1990s - a new type of (four) good comprehensive mechanical properties 'such as high elasticity; set, (10) ^ and low density, and excellent electrical properties, surface properties And (four) miscellaneous. With the change of the way, the current, the f attribute or the semiconductor nature. Due to its ideal-dimensional structure and excellent properties in mechanics and domains, it has a broad application prospect in materials science, chemistry, and physics, and === two-column Among them, the field emission of the carbon nanotubes and the display of the emission of the display device as the field emission of the ancient array of the field to form the cathode of the cathode are two main methods, namely · mechanical method and ^ main: Chang Nai Carbon tube; will grow out. The mechanical method is pre-formed into a hydrosol; long-term storage = separation of the carbon tube, purification of the same column height position, after the sol body 'water soluble... the required stock solution is added to remove; the carbon nanotubes are assembled on a clean metal substrate The surface is shaped like this: 200805415 The cathode is shot. However, the method is also made into water, volume #: long carbon tube purification, separation of sub-1 into water 4, still need to be stored for about one month, which takes a long time, which is not conducive to practical production and application. Original: The vertical growth method is based on the principle of chemical vapor deposition ((3) ::=sltlon, CVD) directly on the substrate to grow the nano-scale transition metal on the substrate, or subtractive material for __ At relatively low, the nanotube array is prepared to form a field emission cathode: its =, dioxo or metal seal. When the base U metal material _, the type of metal material should be selected to avoid the gold = ring = vapor deposition of the growth environment, or form a gold with the catalyst, or because of its own catalytic action, strong decomposition of carbon = 3 ' Can be used as a base metal _ U (four) section on the 'and thus limit its wide application. The field emission cathode formed by the above method mainly comprises a base of a cerium, an emulsified ruthenium or a metal, a full-electrode electrode formed on the substrate, and a metal electric slab or a sulphurite formed on the metal electrode. In the case of eve materials, = stone = train, when the substrate is selected poorly, it will lead to the formation of the field emission cathode on the same electrode, the potential difference, the accumulation of electricity and the growth conditions of the in situ growth method are selected: Time. : 'When the substrate is low due to the corrosion resistance of the acid-resistant domain, 'the micro-addition I of the pure material non-field emission device is not minus the bottom of the base and the three-pole type cathode cathode (4) or: the second emission of 200805415 field emission The device has a low resolution and is not capable of using the field-emitting cathode to make an addressed array. Field emission to overcome the above disadvantages In view of this, it is indeed necessary to provide a cathode and a method of manufacturing the same. [Summary of the Invention]
及盆制^姻實施例進—步詳細說明—種場發射陰極 衣造方法’該場發射陰極包含之金屬電極與奈米 ^官間形成的電阻較小；另，藉由該場發射陰極的製 造方法生長的奈米碳管陣列均勻定向排列從而利於 場發射。 ^種场發射陰極，包括基底、設置於基底上且厚 度爲β〇奈米〜2〇〇奈米的金屬電極以及形成於金屬電 極上的奈米碳管陣列，其中，金屬電極與奈米碳管陣 列之間設置一鋁過渡層，該鋁過渡層的厚度爲5奈米 〜40奈米。 一種場發射陰極的製造方法，係包括以下步驟： 提供一基底； 於基底上形成金屬電極，該金屬電極的厚度爲60 奈米〜200奈米； 於金屬電極上沈積一鋁過渡層，該鋁過渡層的厚 度爲5奈米〜40奈米； 於鋁過渡層上沈積一催化劑層，該催化劑層的厚 度爲3奈米〜1〇奈米； 將沈積有催化劑層、鋁過渡層以及金屬電極的基 200805415 底放置空氣中，於300°C~500°C下熱處理1〇分鐘~l2 小時，催化劑層經退火後形成氧化顆粒； 將基底放置反應裝置中’於反應裴置内通入保護 氣體，於保護氣體的保護下加熱至4〇(rc〜75(rc ·以 及 ， 通入碳源氣與保護氣體的混合氣體，加熱多 400°C〜75(TC反應〇· 5分鐘〜2小時生長出奈米碳管# 列從而形成場發射陰極。 方法中藉由於金屬電極和催化劑之間設And the method of the potting method is described in detail - the field emission cathode coating method "the field emission cathode comprises a metal electrode and the nanometer has a smaller electrical resistance; and, by the field emission cathode The carbon nanotube array grown by the manufacturing method is uniformly aligned to facilitate field emission. a seed emission cathode comprising a substrate, a metal electrode disposed on the substrate and having a thickness of β〇N~2〇〇 nanometer, and an array of carbon nanotubes formed on the metal electrode, wherein the metal electrode and the nanocarbon An aluminum transition layer is disposed between the tube arrays, and the aluminum transition layer has a thickness of 5 nm to 40 nm. A method for manufacturing a field emission cathode includes the steps of: providing a substrate; forming a metal electrode on the substrate, the metal electrode having a thickness of 60 nm to 200 nm; depositing an aluminum transition layer on the metal electrode, the aluminum The thickness of the transition layer is 5 nm to 40 nm; a catalyst layer is deposited on the aluminum transition layer, the catalyst layer has a thickness of 3 nm to 1 Å nanometer; a catalyst layer, an aluminum transition layer, and a metal electrode are deposited The base of 200805415 is placed in the air and heat treated at 300 ° C ~ 500 ° C for 1 ~ ~ l2 hours, the catalyst layer is annealed to form oxidized particles; the substrate is placed in the reaction device to pass the protective gas into the reaction chamber Heated to 4 〇 under the protection of the shielding gas (rc~75 (rc · and, mixed gas of carbon source gas and shielding gas, heating more than 400 ° C ~ 75 (TC reaction 〇 · 5 minutes ~ 2 hours growth The column of carbon nanotubes is formed to form a field emission cathode. The method is based on the arrangement between the metal electrode and the catalyst.
與先前技術相較，本發明的場發射陰極係於金屬€ 極與催化劑間設置-銘過渡層，該叙過渡層既可改善 陰極的導電特性，亦可防止金屬電極與奈米碳管陣列 間産生較大的電阻，另，本發_場發糖極的製遠 【實施方式】Compared with the prior art, the field emission cathode of the present invention is provided between the metal and the catalyst, and the transition layer can improve the conductive property of the cathode and prevent the metal electrode from interposing between the carbon nanotube array and the carbon nanotube array. Produce a large resistance, in addition, the hair of the hair _ field hair remedies [embodiment]
: >閱圖1，本發明場發射陰極1〇〇包括一基底 設置於基底10 ±的金屬電極 極20上的一鋁過渡層3〇 的奈米碳管陣列5〇。 其中，基底10 該場發射陰 ‘屬電極20、設置於金屬電 以及於鋁過渡層30上形成 的材料爲矽或二氧化矽，故使用 極的場發射裝置的冑析度較高且可 9 200805415 址。金屬電極20的厚度爲60奈米〜200奈米，材料可 以選用金、銀、銅或者鉬，其中，鉬具有較高熔點並 且耐強酸尤其是氫氟酸的腐蝕，故而，爲了與三極型 場發射裝置的微加工工藝相兼容，金屬電極2〇的材 料優選鉬。鋁過渡層30的設置可避免於奈米碳管陣 列50及金屬電極2〇間形成大的電阻從而利於場發 射，其厚度爲5奈米〜40奈米，最優地，鋁過渡層3〇 的厚度爲40奈米。奈米碳管陣列5〇中各奈米碳管的 平均直径爲5奈米〜20奈米，平均長度約爲2微米〜2〇 微米。 請參閱圖2，上述的場發射陰極丨⑽的製造方法 主要包括以下幾個步驟： (一） 提供一矽或二氧化矽材料的基底1Q，如矽 基底、石英基底或者玻璃基底； (二） 於基底10上形成金屬電極2〇，該金屬電 極20的厚度爲60奈米〜20〇奈米； 金屬電極20可藉由光刻技術、電子束光刻技術 結合反應離子刻银技術、幹法刻钮技術或者濕法刻姓 技術於基底10上形成，但不以此爲限。 採用光刻技術形成金屬電極2 0的方法包括以下 步驟： 首先將基底10置於真空腔内，以氧化鋅（Ζη0χ)、 銳酸鋰（LiNbOx)、鈦酸鋰（LiTiOx)或者钽酸鋰 (LiTaOx)爲濺鍍靶材，以氬氣（Ar〇與氧氣爲錢鍵 200805415 氣體，於該基底10的表面濺鑛一壓電薄膜層，濺鍵Referring to Figure 1, the field emission cathode 1 of the present invention comprises a carbon nanotube array 5 of an aluminum transition layer 3 基底 disposed on a metal electrode 20 of the substrate 10 ±. Wherein, the substrate 10 emits the cathode electrode 20, the metal electrode and the material formed on the aluminum transition layer 30 are germanium or germanium dioxide, so the field emission device using the pole has a high degree of decantation and can be 9 200805415 address. The metal electrode 20 has a thickness of 60 nm to 200 nm, and the material may be selected from gold, silver, copper or molybdenum. Among them, molybdenum has a higher melting point and is resistant to corrosion by a strong acid, especially hydrofluoric acid, so that in order to be in a three-pole type The microfabrication process of the field emission device is compatible, and the material of the metal electrode 2 is preferably molybdenum. The aluminum transition layer 30 is disposed to avoid formation of a large electrical resistance between the carbon nanotube array 50 and the metal electrode 2 to facilitate field emission, and has a thickness of 5 nm to 40 nm, and optimally, the aluminum transition layer 3〇 The thickness is 40 nm. Each of the carbon nanotubes in the carbon nanotube array has an average diameter of 5 nm to 20 nm and an average length of about 2 μm to 2 μm. Referring to FIG. 2, the method for manufacturing the field emission cathode crucible (10) mainly includes the following steps: (1) providing a substrate 1Q of a germanium or germanium dioxide material, such as a germanium substrate, a quartz substrate or a glass substrate; Forming a metal electrode 2 on the substrate 10, the metal electrode 20 having a thickness of 60 nm to 20 nm; the metal electrode 20 can be combined with a reactive ion etching technique by a photolithography technique, an electron beam lithography technique, or a dry method The button technique or the wet engraving technique is formed on the substrate 10, but is not limited thereto. The method of forming the metal electrode 20 by photolithography includes the following steps: First, the substrate 10 is placed in a vacuum chamber, and zinc oxide (Ζη0χ), lithium niobate (LiNbOx), lithium titanate (LiTiOx) or lithium niobate ( LiTaOx) is a sputtering target, and argon gas (Ar〇 and oxygen as the money bond 200805415 gas, splashing a piezoelectric film layer on the surface of the substrate 10, splashing key
的方法可爲反應性直流濺鍍（DC Reactive Sputtering )或反應性射頻錢鐘（rf Reactive Sputtering)，控制反應參數使得壓電薄膜層的厚度 約爲0· 02〜5微米；於壓電薄膜層表面塗覆一光阻層； 然後將一光罩罩於光阻層表面，該光罩的圖案與所需 金屬電極相對應；用雷射光或紫外光照射該光罩，在 光阻表面形成一曝光區；取下光罩後，將曝光的光阻 g置於顯影液内，去除曝光區的曝光光阻，露出部分 壓電薄膜層；接著藉由濺鍍法於剩餘光阻及露出的部 分屋電薄膜層表面鐘-導電金屬層，導電金屬層的厚 =爲60奈米〜200奈米’材料可選用金、銀、鋼或 、@，其中，錮具有較南溶點並 酸的腐巍扮而…1 強酸特別是氫氣 錢’故而’爲了與二極型場 工藝相兼容，導電金屬層的材料優衣㈣微加工 阻及附著於光阻上的金屬膜層，剩^洗去剩餘光 形成所需的金屬電極20。 、的導電金屬層印 採用濕法刻钱技術形成金屬蕾 以下步驟： ^電極2〇的方法包括 導電金屬:ί電1或濺射的方法形成 點並且#_制是錢 ’銷具有 一極型場發射裝置的微加工工：腐蝕，故而，爲 工藝相兼容，導電^ 11 200805415 層的材料優選相. ^ ^ ' ’將如光致抗钱劑的刻钱保護材料塗 於V電金屬層的表面形成刻蝕保護層；曝光或顯影 去除刻钱保護；士 曰中選定的部分，以便有選擇的露出導 θ ’ ：路出的導電金屬層與刻蝕劑反應以便將 其去除，其中，^ χΙ〗餘劑以電解液的形式施加，電化學 料電金屬層，電紐巾包括不能The method may be reactive DC sputtering (reactive sputtering) or reactive RF clock (rf Reactive Sputtering), and the reaction parameters are controlled so that the thickness of the piezoelectric film layer is about 0.02 to 5 micrometers; Coating a photoresist layer on the surface; then covering a surface of the photoresist layer with a mask corresponding to the desired metal electrode; irradiating the mask with laser light or ultraviolet light to form a surface on the photoresist surface Exposure zone; after removing the mask, the exposed photoresist g is placed in the developer to remove the exposure photoresist in the exposed area to expose a portion of the piezoelectric film layer; then the remaining photoresist and the exposed portion are deposited by sputtering The surface of the electric film layer of the house - the conductive metal layer, the thickness of the conductive metal layer = 60 nm ~ 200 nm 'material can be selected from gold, silver, steel or @, where 锢 has a more southern point and acid rot巍 而 ... 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 A desired metal electrode 20 is formed. The conductive metal layer is printed by a wet engraving technique to form a metal bud. The following steps are performed: ^ Electrode 2 〇 method includes conductive metal: ί electric 1 or sputtering method forms a point and #_制是钱' pin has a pole type The micro-machining device of the field emission device: corrosion, and therefore, compatible with the process, the material of the conductive layer is preferably the phase. ^ ^ ' ' Applying the engraving protection material such as photo-anti-moisture agent to the V-electrode metal layer An etch protection layer is formed on the surface; exposure or development removes the engraved protection; the selected portion of the gentry is selected to selectively expose the θ ' : the outgoing conductive metal layer reacts with the etchant to remove it, wherein χΙ〗 The residual agent is applied in the form of an electrolyte, the electrochemical material is a metal layer, and the electric towel includes
、J飿的方式與導電金屬層反應的中性鹽、酸或域以 及能约以刻飯太4 ^ 万式與露出的導電金屬層反應的化學 氧化成分；利用古α 用有機物溶劑如純丙酮有機物溶劑去降 =餘的刻純_料，祕保料下覆 導 電金屬層㈣成所需的金屬電極。 ]餘¥ 、./ (一）在金屬電極20上藉由蒸鍍或者濺射的方 法开7成一銘層30作爲過渡層，紹過渡層30的厚度爲 5奈米〜40奈米，最優地，鋁過渡層30的厚度爲4η 太企· ^ υ (四）於鋁過渡層30上形成催化劑層4〇，催化 劑可選用鐵（Fe)、鈷（Co)、鎳（Ni)或者其任意魬 合的合金之一，催化劑層40的厚度與催化劑的種類 相對應，當選用鐵作爲催化劑時，鐵催化劑層的厚声 爲3奈米〜1〇奈米，優選地，鐵催化劑層的厚度爲$ 奈米； (五）將沈積有催化劑層4 0、紹過渡層3 〇及金 屬電極20的基底1〇放置空氣中，於300°C〜500°c下 熱處理10分鐘〜12小時，催化劑層40經退火後形成 12 200805415 _ 氧化顆粒； ^ (六）將基底10放置於適於化學氣相沈積 (Chemical Vapor Deposition，CVD)反應的反應裝 置（圖中未顯示）中，於反應裝置内通入保護氣體， 於保護氣體的保護下加熱到一預定溫度，通入碳源氣 與保護氣體的混合氣體，加熱至400°C〜750°C反應〇· 5 分鐘〜2小時生長出奈米碳管陣列50從而形成場發射 陰極1 〇 〇。 其中，預先通入保護氣體加熱到預定溫度的作用 係防止催化劑層形成的氧化顆粒於奈米碳管陣列50 的生長過程中進一步被氧化從而影響奈米碳管陣列 50的生長條件，該預定溫度因使用的催化劑不同而不 同，一般爲400°C〜750°C，當選用鐵作爲催化劑時， 預定溫度優選爲6 5 0 C ’另外’預先加熱時使用的保 護氣體爲惰性氣體或氮氣，優選地，保護氣體爲氬 馨 氣。於預先加熱過程後，可通入氫氣或者氨氣還原催 化劑層形成的氧化顆粒從而得到奈米級的催化劑顆 教410，另，在通入碳源氣加熱時，碳源氣分解也可 將氧化顆粒還原形成奈米級的催化劑顆粒410，故 而，通入氫氣或者氨氣還原的過程不是必須，可根據 實際情況選擇。碳源氣與保護氣體的混合氣體中的碳 源氣爲碳氫化合物，可爲乙炔、乙稀等，優選地，碳 源氣爲乙炔；保護氣體爲惰性氣體或者氮氣，優選 地，保護氣體爲氬氣。 13 200805415 ^清參閱圖3 ’圖3係依據本發明場發射陰極的製 =方法所得到的場發射陰極中奈米碳管陣列的掃描 笔子”、、頁微鏡（Scanning Electron Microscope，SEM) =片/照片中顯示的奈米碳管的平均直徑爲5奈米〜2〇 不米平均長度約爲2微米〜20微米。具體步驟大致 上匕括·提供一二氧化矽基底；於二氧化矽基底上濺 射厚度約爲100奈米的鉬層，然後藉由濕法刻蝕技術 形成所需的鉬電極；於鉬電極上濺射厚度約爲37奈 米的鋁過渡層；於鋁過渡層上濺射厚度約爲5奈米的 鐵層作爲催化劑層；將沈積有鐵催化劑層、鉬電極及 鋁過渡層的基底放置於空氣中，於約300°C下熱處理 約10分鐘，退火後鐵催化劑層形成氧化鐵顆粒；將 帶有氧化鐵顆粒的基底放置於石英反應舟中，將反應 2裝入管狀石英爐中央的反應室内，通人氬氣加熱至 約65(TC ·，通入氩氣使氧化鐵顆粒還原形成奈米級的 鐵催化劑顆粒；通入乙炔及氬氣的混合氣體，加熱至 約7〇〇°C，反應約20分鐘生長出奈米碳管陣列從而形 成場發射陰極。 ^請參閱圖4,圖4係依據本發明場發射陰極的製 造方法得到的另一場發射陰極中奈米碳管陣列的sem 照片，照片中顯示的奈米碳管的平均直徑爲5奈米〜2〇 不米’平均長度約爲2微米〜20微米。具體步驟大致 上包括：提供一矽基底；於矽基底上濺射厚度約爲176 奈米的鉬層，然後藉由濕法刻蝕技術形成所需的鉬電 14 200805415 極；於鉬電極上濺射厚度約爲4〇奈米的鋁過渡層； 於鋁過渡層上濺射厚度約爲5奈米的鐵層作爲催化劑 層；將沈積有鐵催化劑層、鉬電極及鋁過渡層的基底 放置於空氣中，於約3〇{TC下熱處理約10分鐘t退 火後鐵催化劑層形成氧化鐵顆粒；將帶有氧化鐵顆粒 的基底放置於石英反應舟中，將反應舟裝入管狀石英 爐中央的反應室内，通入氬氣加熱至約65(rc;通入 氳氣使氧化鐵顆粒還原形成奈米級的鐵催化劑顆 粒，通入乙炔及氬氣的混合氣體，加熱至約。〇， 反應約20分鐘生長出奈米碳管陣列從而形成場發射 陰極。 ' 請參閱圖5，圖5係依據先前技術的場發射陰極 的製造方法得到的場發射陰極中奈米碳管的SEr照 片，於該先前的場發射陰極的製造方法中不含鋁過渡 層而其他生長條件與本發明場發射陰極的製造方法 中的生長條件相同。由圖3、圖4和圖5的對比可知， 本發明場發射陰極的製造方法所得到的場發射陰極 1〇〇中各奈米碳管均勻定向㈣，而不採魏過渡層 生長的場發射陰極中㈣米管較爲稀疏，且未能定向 排列。 綜上所述，本發明確已符合發明專利之要件，遂依法 提出專利申請。惟，以上所述者僅為本發明之較佳實施例， 自不月b以此限制本案之φ請專利範圍。舉凡熟悉本案技藝 之人士援依本發明之精神所作之等效修飾或變化，皆應涵 15 200805415 . 蓋於以下申請專利範園内。 【圖式簡單說明】 意 圖1係本發明場發射陰極的結構示意圖。 圖2係圖1的場發射陰極的製造方法的流程示意 圖。 圖3係依據本發明場發射陰極的製造方法得到的 場發射陰極中奈米碳管陣列的掃描電子顯微鏡 . (Scanning Electron Microscope，SEM)照片。 圖4係依據本發明場發射陰極的製造方法得到的 另一場發射陰極中奈米碳管陣列的SEM照片。 圖5係依據先前技術的場發射陰極的製造方法得 到的場發射陰極中奈米碳管的SEM照片。 【主要元件符號說明】 場發射陰極 100 基底 10 _ 金屬電極 20 銘過渡層 3〇 催化剂层 40 催化剂颗粒 410 奈米後管陣列 5〇 16a neutral salt, acid or domain in which the J饳 is reacted with the conductive metal layer, and a chemical oxidizing component capable of reacting with the exposed conductive metal layer in a manner of about 4 million types; using an organic solvent such as pure acetone The organic solvent is degraded = the remaining pure material, the secret material is covered with a conductive metal layer (4) into the desired metal electrode. ] ¥, . / (1) On the metal electrode 20 by evaporation or sputtering method to open a layer of a layer 30 as a transition layer, the thickness of the transition layer 30 is 5 nm ~ 40 nm, the best The thickness of the aluminum transition layer 30 is 4η 企 · ^ 四 四 四 四 四 四 四 四 四 四 四 四 四 四 四 四 四 四 四 四 四 四 四 四 四 四 四 四 四 四 四 四 四 四 四 四 四 四 四 四 四 四 四 四One of the alloys to be alloyed, the thickness of the catalyst layer 40 corresponds to the type of the catalyst. When iron is selected as the catalyst, the thickness of the iron catalyst layer is 3 nm to 1 Å, preferably, the thickness of the iron catalyst layer. (5) The substrate 1 deposited with the catalyst layer 40, the transition layer 3 and the metal electrode 20 is placed in air, and heat treated at 300 ° C to 500 ° C for 10 minutes to 12 hours, the catalyst The layer 40 is annealed to form 12 200805415 _ oxidized particles; ^ (6) The substrate 10 is placed in a reaction device (not shown) suitable for chemical vapor deposition (CVD) reaction, in the reaction device Passing a protective gas and heating it to a predetermined temperature under the protection of a protective gas, A mixed gas of a carbon source gas and a shielding gas is introduced, and heated to 400 ° C to 750 ° C for a reaction time of 5 minutes to 2 hours to grow the carbon nanotube array 50 to form a field emission cathode 1 〇 〇. Wherein, the pre-passing of the protective gas to the predetermined temperature prevents the oxidation particles formed by the catalyst layer from being further oxidized during the growth of the carbon nanotube array 50 to affect the growth conditions of the carbon nanotube array 50, the predetermined temperature. Depending on the catalyst used, it is generally 400 ° C ~ 750 ° C, when the choice of iron as a catalyst, the predetermined temperature is preferably 6 5 0 C 'other 'the protective gas used in the preheating is inert gas or nitrogen, preferably Ground, the shielding gas is argon. After the pre-heating process, the oxidized particles formed by the reduction of the catalyst layer by hydrogen or ammonia gas may be introduced to obtain a catalyst catalyst 410 of the nano-scale. Further, when the carbon source gas is heated, the decomposition of the carbon source gas may also be oxidized. The particles are reduced to form nano-sized catalyst particles 410. Therefore, the process of introducing hydrogen or ammonia gas is not necessary, and may be selected according to actual conditions. The carbon source gas in the mixed gas of the carbon source gas and the shielding gas is a hydrocarbon, which may be acetylene, ethylene or the like. Preferably, the carbon source gas is acetylene; the shielding gas is an inert gas or nitrogen gas, preferably, the shielding gas is Argon. 13 200805415 ^See Fig. 3 'Fig. 3 is a scanning pen of a carbon nanotube array in a field emission cathode obtained according to the method for producing a field emission cathode according to the present invention," Scanning Electron Microscope (SEM) = The average diameter of the carbon nanotubes shown in the film/photograph is 5 nm ~ 2 〇 The average length of the rice is about 2 μm to 20 μm. The specific steps are roughly as follows: provide a cerium oxide substrate; A molybdenum layer having a thickness of about 100 nm is sputtered on the crucible substrate, and then a desired molybdenum electrode is formed by a wet etching technique; an aluminum transition layer having a thickness of about 37 nm is sputtered on the molybdenum electrode; An iron layer having a thickness of about 5 nm is sputtered on the layer as a catalyst layer; a substrate on which an iron catalyst layer, a molybdenum electrode, and an aluminum transition layer are deposited is placed in the air, and heat-treated at about 300 ° C for about 10 minutes, after annealing. The iron catalyst layer forms iron oxide particles; the substrate with iron oxide particles is placed in a quartz reaction boat, and the reaction 2 is charged into a reaction chamber in the center of the tubular quartz furnace, and heated by an argon gas to about 65 (TC ·, access) Argon reduces the iron oxide particles Nano-sized iron catalyst particles; a mixed gas of acetylene and argon is introduced, heated to about 7 ° C, and a carbon nanotube array is grown for about 20 minutes to form a field emission cathode. ^ Please refer to FIG. Figure 4 is a sem photograph of a carbon nanotube array in another field emission cathode obtained according to the method for fabricating a field emission cathode of the present invention. The average diameter of the carbon nanotubes shown in the photograph is 5 nm ~ 2 〇 not metre 'average The length is about 2 micrometers to 20 micrometers. The specific steps generally include: providing a germanium substrate; sputtering a molybdenum layer having a thickness of about 176 nm on the germanium substrate, and then forming the desired molybdenum electricity by wet etching 14 200805415 pole; sputtering an aluminum transition layer with a thickness of about 4 nanometers on the molybdenum electrode; sputtering an iron layer having a thickness of about 5 nanometers as a catalyst layer on the aluminum transition layer; depositing an iron catalyst layer, molybdenum The substrate of the electrode and the aluminum transition layer is placed in the air, and the iron catalyst layer forms iron oxide particles after annealing at about 3 Torr for about 10 minutes. The substrate with the iron oxide particles is placed in the quartz reaction boat. Reaction boat loaded into tubular stone In the reaction chamber in the center of the furnace, argon gas is heated to about 65 (rc; the helium gas is introduced to reduce the iron oxide particles to form nano-sized iron catalyst particles, and a mixed gas of acetylene and argon is introduced, and heated to about 〇. The reaction develops a carbon nanotube array for about 20 minutes to form a field emission cathode. 'Please refer to FIG. 5, which is a SEr photograph of a carbon nanotube in a field emission cathode obtained according to the prior art field emission cathode manufacturing method. In the manufacturing method of the previous field emission cathode, the aluminum transition layer is not contained and the other growth conditions are the same as those in the manufacturing method of the field emission cathode of the present invention. As can be seen from the comparison of FIG. 3, FIG. 4 and FIG. In the field emission cathode of the invention, the nano-carbon tubes in the field emission cathode are uniformly oriented (4), and the field emission cathodes which are not grown in the Wei transition layer are sparse and not oriented. . In summary, the present invention has indeed met the requirements of the invention patent, and has filed a patent application according to law. However, the above description is only a preferred embodiment of the present invention, and the scope of the patent application of this case is limited by this. Any equivalent modifications or variations made by those who are familiar with the skill of the present invention in accordance with the spirit of the present invention shall be covered by the following application. BRIEF DESCRIPTION OF THE DRAWINGS Fig. 1 is a schematic view showing the structure of a field emission cathode of the present invention. Fig. 2 is a schematic flow chart showing a method of manufacturing the field emission cathode of Fig. 1. Figure 3 is a scanning electron microscopy (SEM) photograph of a carbon nanotube array in a field emission cathode obtained in accordance with the method of fabricating a field emission cathode of the present invention. Figure 4 is a SEM photograph of a carbon nanotube array in another field of emission cathode obtained in accordance with the method of fabricating a field emission cathode of the present invention. Figure 5 is a SEM photograph of a carbon nanotube in a field emission cathode obtained in accordance with the prior art method of fabricating a field emission cathode. [Main component symbol description] Field emission cathode 100 Substrate 10 _ Metal electrode 20 Ming transition layer 3〇 Catalyst layer 40 Catalyst particles 410 Nanotube array 5〇 16