1293813 九、發明說明： 【發明所屬之技術領域】 本發明是有關於一種發光二極體及其製造方法，特別 是指一種具有附著反射層的垂直式發光二極體及其製造方 法。 【先前技術】 目前GaN基白光發光二極體（GaN-LED)，已大量應用 1 在照明及顯示設備上，如何提高其發光效率、輸出功率，BACKGROUND OF THE INVENTION 1. Field of the Invention This invention relates to a light-emitting diode and a method of fabricating the same, and more particularly to a vertical light-emitting diode having an attached reflective layer and a method of fabricating the same. [Prior Art] At present, GaN-based white light-emitting diode (GaN-LED) has been widely used. 1 How to improve its luminous efficiency and output power in lighting and display devices.
B 及更高流明通量已成為白光LED發展之必然趨勢。在GaN 基LED的磊晶製程上，一般係以藍寶石絕緣基板作為主動 層（active layer)之蠢晶基板，以獲得較佳結晶品質的主動層 。然而藍寶石基板的導電性及導熱性不良，限制傳統GaN 基LED之正、負電極製作只能採用同置一側之橫向結構， 此種結構除了需涉及磊晶層蝕刻製程外，亦導致嚴重電流 擁擠效應（current crowding)，造成高順向偏壓之缺失，使得 發展高效率、高輸出功率之LED深受限制。 ® 為了改善上述藍寶石基板所衍生之導電與導熱的問題 “ ，現行作法之一是於藍寶石基板上成長GaN基磊晶層後， 利用電鍍方式於GaN基磊晶層上，形成一層導電性及導熱 性佳的鎳金屬薄膜作為承載，再使用雷射剝離法（laser liftoff)剝離藍寶石基板，使GaN基磊晶層最後是位於鎳金 屬薄膜上，如此一來，即可製作成垂直式的GaN基LED。 由於鎳金屬薄膜具有極佳的機械強度，可以增加GaN 基磊晶層之支撐力，因此在雷射剝離過程中，是作為承載 1293813B and higher lumen fluxes have become an inevitable trend in the development of white LEDs. In the epitaxial process of GaN-based LEDs, a sapphire insulating substrate is generally used as a stray substrate of an active layer to obtain an active layer of better crystal quality. However, the conductivity and thermal conductivity of the sapphire substrate are poor, and the fabrication of the positive and negative electrodes of the conventional GaN-based LED can only be achieved by using the lateral structure of the same side. This structure not only involves the epitaxial layer etching process, but also causes severe current. Current crowding, the lack of high forward bias, makes the development of high efficiency, high output LEDs very limited. In order to improve the conductivity and thermal conductivity of the sapphire substrate, one of the current methods is to form a layer of conductivity and heat conduction on the GaN-based epitaxial layer by galvanizing the GaN-based epitaxial layer on the sapphire substrate. A good nickel metal film is used as a load, and the sapphire substrate is peeled off by a laser liftoff method, so that the GaN-based epitaxial layer is finally placed on the nickel metal film, so that a vertical GaN group can be fabricated. LED. Since the nickel metal film has excellent mechanical strength, it can increase the supporting force of the GaN-based epitaxial layer, so it is used as the bearing 1293813 during the laser stripping process.
GaN基磊晶層的支持基板。然而電鍍的鎳金屬與GaN基磊 晶層間的應力、附著力，及電性接觸良好與否，都是影響 雷射剝離法置換基板能否成功的重要關鍵，且對於後續製 作成LED元件時，是否能提高發光功率、元件良率，皆有 相當的影響。 【發明内容】 因此，本發明之目的，即在提供一種有效降低支持基 板與氮化鎵基磊晶層間的應力，並可提高產品良率及發光 功率之具有附著反射層的垂直式發光二極體及其製造方法 〇 於是，本發明垂直式發光二極體包含：一支持基板、 一位於支持基板上的附著反射層單元、一位於附著反射層 單元上的金屬接觸層單元、一位於金屬接觸層單元上的發 光單元，以及一位於發光單元上的電極。 該支持基板是金屬材料或半導體材料所製成的。 該附著反射層單元包括四層附著反射層，該等附著反 射層是選自下列材料：鈦（Ti)、鋁（A1)、金（Au)、鎳（Ni)、銀 (Ag)、鉑（Pt)、鈀（Pd)、金/辞（Au/Zn)、金/鈹（Au/Be)、金/鍺 (Au/Ge)、金/鍺/鎳（Au/Ge/Ni)、銦（In)、錫（Sn)、鋅（Zn)所構 成之群組，及其組合。 更具體而言，本發明可選用金（Au)、鈦（Ti)、鋁（A1)、 鈦（Ti)等材料來製作該等附著反射層，上述附著反射層之排 列方式係以金附著反射層最靠近支持基板，依序為一層鈦 附著反射層、一層鋁附著反射層，最後再設置一層鈦附著 1293813 反射層，所述鈦附著反射層的厚度是介於10〜150 nm、金 附著反射層的厚度是介於50〜350 nm、I呂附著反射層的厚 度是介於200〜600 nm。 而本發明垂直式發光二極體之製造方法包含以下步驟 (1) 準備一轉換基板。 (2) 在該轉換基板上成長一緩衝層（buffer layer)。 (3) 在該緩衝層上成長該發光單元。 (4) 在該發光單元上沉積該金屬接觸層單元。 (5) 在該金屬接觸層單元上沉積該附著反射層單元，所 述附著反射層單元包括四層彼此堆疊之附著反射層。 (6) 在該附著反射層單元上沉積該支持基板。 (7) 移除該轉換基板及緩衝層。 (8) 在該發光單元上沉積該電極。 上述步驟（1)之轉換基板是選自：砷化鎵（GaAs)基板、 藍寶石（Al2〇3)基板及磷化銦（InP)基板所構成之群組。 步驟（5)之附著反射層單元係利用蒸鍍、濺鍍或離子鍍 法沉積於該金屬接觸層單元上。 步驟（6)之支持基板係可以利用電鍍金屬材料的方法， 或者是半導體晶圓接合（wafer bonding)的方式形成於該附著 反射層單元上。 步驟（7)是使用雷射剝離法來移除轉換基板，所使用的 雷射光源為準分子雷射光（excimer laser)。 藉由該附著反射層單元的設置，可以使發光單元與支 1293813 持基板間有良好的結合附著力，以利於承受雷射剝離製程 的高溫，且該附著反射層單元更具備有光反射的功能，可 、將lx光單元產生之部分朝支持基板行進的光，往該電極 方向反射，以增加發光二極體的發光效率。且前述附著反 射層單元與支持基板間，及附著反射層單元與金屬接觸層 單70間’具有優異之歐姆接觸，可以有效降低發光二極體 的串聯電阻以及順向偏壓。 【實施方式】 有關本發明之前述及其他技術内容、特點與功效，在 以下配合參考圖式之一個較佳實施例的詳細說明中，將可 清楚的呈現。 參閱圖1，本發明垂直式發光二極體之一較佳實施例包 含：一支持基板26、一位於支持基板26上的附著反射層單 元25、一位於附著反射層單元25上的金屬接觸層單元24 、一位於金屬接觸層單元24上的發光單元23，以及一位於 發光單元23上的電極27。 丨 本實施例之支持基板26是鎳金屬電鍍薄膜。該附著反 射層單元25包括：一鄰近支持基板26之金附著反射層254 、一堆疊在該金附著反射層254上的鈦附著反射層253、一 位於鈦附著反射層253上的鋁附著反射層252，以及一位於 鋁附著反射層252上的鈦附著反射層251，其中金附著反射 層254之厚度為200nm，該等鈦附著反射層253、251之厚 度分別為1〇〇 nm及15 nm，而鋁附著反射層252之厚度為 400nm 〇 1293813 本發明之附著反射層單元25與該支持基板26間，具 有良好的歐姆接觸，其特徵接觸電阻（SCR)值約為ι〇-4〜1〇-5Ώ cm2 〇 本實施例之金屬接觸層單元24包括一彼覆在鈦附著反 射層251上的金（Au)金屬接觸層242,以及一彼覆在該金 (Au)金屬接觸層242上的鎳（Ni)金屬接觸層241。該金屬接 觸層單元24與附著反射層單元25間，接觸電阻（SCR)值亦 約為 1〇-4〜l〇-5Qcm2 。A support substrate for a GaN-based epitaxial layer. However, the stress, adhesion, and electrical contact between the plated nickel metal and the GaN-based epitaxial layer are both important factors affecting the success of the laser stripping method, and for subsequent LED elements. Whether it can improve the luminous power and component yield has a considerable impact. SUMMARY OF THE INVENTION Accordingly, it is an object of the present invention to provide a vertical light-emitting diode with an attached reflective layer that provides an effective adhesion reduction between the support substrate and the gallium nitride-based epitaxial layer and improves product yield and light-emitting power. Body and manufacturing method thereof, wherein the vertical light emitting diode of the present invention comprises: a supporting substrate, an attached reflective layer unit on the supporting substrate, a metal contact layer unit on the attached reflective layer unit, and a metal contact a light unit on the layer unit and an electrode on the light unit. The support substrate is made of a metal material or a semiconductor material. The attached reflective layer unit comprises four layers of attached reflective layers selected from the group consisting of titanium (Ti), aluminum (A1), gold (Au), nickel (Ni), silver (Ag), platinum ( Pt), palladium (Pd), gold / abbreviated (Au / Zn), gold / bismuth (Au / Be), gold / bismuth (Au / Ge), gold / bismuth / nickel (Au / Ge / Ni), indium ( Groups of In), tin (Sn), and zinc (Zn), and combinations thereof. More specifically, the present invention may be made of materials such as gold (Au), titanium (Ti), aluminum (Al), titanium (Ti), etc., and the adhesion reflection layer is arranged by gold adhesion reflection. The layer is closest to the supporting substrate, followed by a layer of titanium attached reflective layer, an aluminum attached reflective layer, and finally a layer of titanium attached 1293813 reflective layer, the thickness of the titanium attached reflective layer is between 10 and 150 nm, and the gold is attached to the reflection layer. The thickness of the layer is between 50 and 350 nm, and the thickness of the I-attachment reflective layer is between 200 and 600 nm. The method of manufacturing the vertical light-emitting diode of the present invention comprises the following steps (1) preparing a conversion substrate. (2) A buffer layer is grown on the conversion substrate. (3) The light-emitting unit is grown on the buffer layer. (4) depositing the metal contact layer unit on the light emitting unit. (5) depositing the adhesion reflective layer unit on the metal contact layer unit, the adhesion reflection layer unit comprising four layers of an adhesion reflection layer stacked on each other. (6) depositing the support substrate on the attached reflective layer unit. (7) The conversion substrate and the buffer layer are removed. (8) depositing the electrode on the light emitting unit. The conversion substrate of the above step (1) is selected from the group consisting of a gallium arsenide (GaAs) substrate, a sapphire (Al 2 〇 3) substrate, and an indium phosphide (InP) substrate. The attached reflective layer unit of the step (5) is deposited on the metal contact layer unit by evaporation, sputtering or ion plating. The support substrate of the step (6) may be formed on the adhesion reflective layer unit by a method of plating a metal material or by semiconductor wafer bonding. Step (7) is to remove the conversion substrate by using a laser lift-off method, and the laser light source used is an excimer laser. By the arrangement of the attached reflective layer unit, the light-emitting unit and the support 1293813 have good adhesion between the substrates, so as to facilitate the high temperature of the laser stripping process, and the attached reflective layer unit is further provided with light reflection function. The light generated by the portion of the lx light unit toward the support substrate is reflected toward the electrode to increase the luminous efficiency of the light emitting diode. Moreover, the excellent adhesion ohmic contact between the adhesion reflective layer unit and the support substrate, and between the adhesion reflection layer unit and the metal contact layer unit 70 can effectively reduce the series resistance and the forward bias of the light-emitting diode. The above and other technical contents, features, and advantages of the present invention will be apparent from the following detailed description of the preferred embodiments. Referring to FIG. 1, a preferred embodiment of a vertical light-emitting diode of the present invention comprises: a support substrate 26, an attached reflective layer unit 25 on the support substrate 26, and a metal contact layer on the attached reflective layer unit 25. The unit 24, a light-emitting unit 23 on the metal contact layer unit 24, and an electrode 27 on the light-emitting unit 23. The support substrate 26 of the present embodiment is a nickel metal plated film. The adhesion reflective layer unit 25 includes: a gold adhesion reflective layer 254 adjacent to the support substrate 26, a titanium adhesion reflection layer 253 stacked on the gold adhesion reflection layer 254, and an aluminum adhesion reflection layer on the titanium adhesion reflection layer 253. 252, and a titanium adhesion reflective layer 251 on the aluminum adhesion reflective layer 252, wherein the thickness of the gold adhesion reflection layer 254 is 200 nm, and the thickness of the titanium adhesion reflection layers 253, 251 are 1 〇〇 nm and 15 nm, respectively. The aluminum adhesion reflective layer 252 has a thickness of 400 nm 〇 1293813. The adhesion reflective layer unit 25 of the present invention and the support substrate 26 have good ohmic contact, and the characteristic contact resistance (SCR) value is about ι〇-4~1〇. -5 Ώ cm2 金属 The metal contact layer unit 24 of the present embodiment includes a gold (Au) metal contact layer 242 overlying the titanium adhesion reflective layer 251, and a metal overlying the (Au) metal contact layer 242. Nickel (Ni) metal contact layer 241. The contact resistance (SCR) value between the metal contact layer unit 24 and the attached reflective layer unit 25 is also about 1 〇 -4 to l 〇 -5 Qcm 2 .
該發光單元23則是包括一層由ρ型氮化鎵（p_GaN)製成 的第一披覆層233、一位於第一披覆層233上的主動層232 ，以及一位於主動層232上並由n型氮化鎵（n-GaN)製成的 第二彼覆層231。其中主動層232介於該等披覆層233、 231間，且該主動層232可以為涵蓋GaN系的同質結構、 異質結構，或量子井結構，故本發明主要是提供一種垂直 式的GaN基發光二極體。而該第一披覆層233鄰近金屬接 觸單元24。The light emitting unit 23 includes a first cladding layer 233 made of p-type gallium nitride (p_GaN), an active layer 232 on the first cladding layer 233, and an active layer 232. A second cladding layer 231 made of n-type gallium nitride (n-GaN). The active layer 232 is interposed between the cladding layers 233 and 231, and the active layer 232 may be a homogenous structure, a heterostructure, or a quantum well structure covering a GaN system. Therefore, the present invention mainly provides a vertical GaN-based structure. Light-emitting diode. The first cladding layer 233 is adjacent to the metal contact unit 24.
本實施例之電極27包括··一鄰近發光單元23之鈦導 電層271、 鋁導電層 一位在鈦導電層271上的鋁導電層272、一位在 272上的鈥導電層273，以及一位在該鈦導電層 273上的金導電層274。 參閱圖2、3、4,本發明垂直式發光二極體之製造方法 包含以下步驟： (1)進仃步驟U ••準備一個藍寶石轉換基板2ι。 )、行v驟12·在轉換基板21上成長一層QaN緩衝 9 1293813 層22。 (3) 進行步驟13 :在GaN緩衝層22上成長該發光單元 23，成長的步驟係先於GaN缓衝層22上成長一層n_GaN 的第二披覆層231，再於該第二彼覆層231上成長一層具有 多重量子井（Multi Quantum Well)結構的主動層232，最後於 主動層232上成長一層p-GaN的第一彼覆層233。 (4) 進行步驟14:於發光單元23上沉積金屬接觸層單元 24，包含以下製程： (4-1)活化（activation):將進行完步驟11〜13的試片置入 一通入空氣的爐管内（圖未示），爐管内的溫度維持在750°C ，活化時間持續20分鐘，以將p-GaN載子濃度提高約達 1〜2 X 1017 cm·3左右。經由此活化製程使p-GaN摻雜離子化 ，因此在提高P-GaN第一披覆層233之載子濃度的同時， 亦可以增加導電率，並降低接觸電阻。 (4-2)薄化及拋光：對藍寶石轉換基板21進行薄化及拋 光加工，使其厚度達到400 μπι左右，此製程主要是減少後 續在雷射剝離製程中，準分子雷射光透過藍寶石轉換基板 21後，產生的能量損耗。 (4-3)清洗：取硫酸（H2S04)溶液及雙氧水（Η202)溶液以3 :1的比例混合，將試片浸泡在該混合溶液中維持3分鐘， 再浸入去離子水（DI water)中清洗10分鐘，接著浸泡氫氟酸 溶液2分鐘，最後再度浸入DI water清洗10分鐘，取出吹 乾。 (4-4)沉積金屬接觸層單元24:此步驟可以使p-GaN第 10 1293813 一彼覆層233與後續成長的Ni金屬支持基板26間，有良 好的歐姆接觸（ohmic contact)。利用電子束（E-beam)蒸鍍的 方式，於第一彼覆層233上成長2.5nm的鎳金屬接觸層241 ，再於鎳金屬接觸層241上成長4.5nm的金金屬接觸層242 。將試片置於爐管中，在550°C的溫度於氧氣氛圍下退火 (annealing)lO分鐘，並形成鎳、金的金屬氧化物（oxidized-Ni/Au)，即完成p型區欠姆接觸。 ~ (5)進行步驟15:利用E-beam蒸鍍方式在金屬接觸層 B 單元24上沉積附著反射層單元25，沉積順序係於金金屬接 觸層242上依序成長15nm的鈦附著反射層251、400nm的 鋁附著反射層252、100 nm的鈦附著反射層253，以及 200nm的金附著反射層254。 (6) 進行步驟16 :用於沉積支持基板26，首先將硫酸及 雙氧水以3 : 1的比例混合，把已進行至步驟15的試片放 入混合溶液中，溫度維持60QC並浸泡60秒，目的在於增 加附著反射層單元25表面潔淨度及電鍍附著力，隨即浸入 ® 去離子水清洗10分鐘，取出後吹乾。 利用電鍍的方式，於金附著反射層254上電鍍形成一 層由鎳金屬所構成之支持基板26。 (7) 進行步驟17:用於移除轉換基板21及緩衝層22, 即使用波長為248nm的KrF準分子雷射光，由轉換基板21 側照入，使GaN缓衝層22在鄰近轉換基板21之一側解離 產生氮氣及鎵，解離後氮氣會填塞於緩衝層22與轉換基板 21之間，使轉換基板21易於剝離，而後再將試片加熱至 11 1293813 30〜40°C左右，即可將轉換基板21剝離，而由緩衝層22及 發光單元23所構成的GaN基磊晶薄膜，則是完整的位在鎳 金屬支持基板26上，由於雷射剝離法為習用技術，故不再 詳細說明。 接著使用感應搞合電聚（Inductively coupled plasma， 簡稱ICP)蝕刻，移除位在η-GaN第二彼覆層231上的 GaN緩衝層22。 參閱圖5，圖片為完成步驟17後，左邊是剝離後之藍 I1 寶石轉換基板21，右邊為電鍍鎳金屬之支持基板26,其上 保留有完整之GaN基磊晶薄膜。 圖6是利用掃描式電子顯微鏡（SEM)，拍攝位在鎳金屬 支持基板上的GaN基磊晶薄膜的圖片。 (8)進行步驟18 :用於沉積電極27，即如圖1所示，經 由化學溶液處理後，在第二披覆層231上依序沉積鈦導電 層271、鋁導電層272、鈦導電層273，以及金導電層274 ，藉此以形成η型接觸，如此即完成本發明垂直式發光二 ’極體結構的製作。The electrode 27 of the present embodiment includes a titanium conductive layer 271 adjacent to the light-emitting unit 23, an aluminum conductive layer 272 having an aluminum conductive layer on the titanium conductive layer 271, a tantalum conductive layer 273 on the 272, and a A gold conductive layer 274 is disposed on the titanium conductive layer 273. Referring to Figures 2, 3 and 4, the manufacturing method of the vertical light-emitting diode of the present invention comprises the following steps: (1) Stepping step U • Preparing a sapphire conversion substrate 2ι. ), step v12. A layer of QaN buffer 9 1293813 is formed on the conversion substrate 21. (3) Step 13: growing the light-emitting unit 23 on the GaN buffer layer 22, the step of growing is to grow a second cladding layer 231 of n-GaN on the GaN buffer layer 22, and then to the second cladding layer An active layer 232 having a multi-quantum well structure is grown on the 231, and finally a first sub-layer 233 of p-GaN is grown on the active layer 232. (4) Performing step 14: depositing a metal contact layer unit 24 on the light-emitting unit 23, comprising the following processes: (4-1) activation: placing the test piece subjected to steps 11 to 13 into an air-passing furnace In the tube (not shown), the temperature in the tube was maintained at 750 ° C and the activation time was continued for 20 minutes to increase the p-GaN carrier concentration by about 1 to 2 X 1017 cm·3. By this activation process, p-GaN is ion-doped, so that while increasing the carrier concentration of the P-GaN first cladding layer 233, the conductivity can be increased and the contact resistance can be lowered. (4-2) Thinning and Polishing: The sapphire conversion substrate 21 is thinned and polished to a thickness of about 400 μπι. This process mainly reduces the subsequent conversion of excimer laser light through sapphire in the laser stripping process. After the substrate 21, the energy loss is generated. (4-3) Cleaning: Mix sulfuric acid (H2S04) solution and hydrogen peroxide (Η202) solution in a ratio of 3:1, soak the test piece in the mixed solution for 3 minutes, and then immerse it in DI water. After washing for 10 minutes, the hydrofluoric acid solution was immersed for 2 minutes, and finally immersed in DI water for 10 minutes, and taken out and dried. (4-4) Depositing the metal contact layer unit 24: This step allows a good ohmic contact between the p-GaN 101293813 and the subsequent grown Ni metal supporting substrate 26. A nickel metal contact layer 241 of 2.5 nm was grown on the first cladding layer 233 by electron beam (E-beam) vapor deposition, and a gold metal contact layer 242 of 4.5 nm was grown on the nickel metal contact layer 241. The test piece was placed in a furnace tube, annealed at a temperature of 550 ° C in an oxygen atmosphere for 10 minutes, and a nickel-gold metal oxide (oxidized-Ni/Au) was formed, that is, the p-type region was completed. contact. ~ (5) Performing step 15: depositing an adhesion reflective layer unit 25 on the metal contact layer B unit 24 by means of E-beam evaporation, and depositing a titanium adhesion reflective layer 251 of 15 nm in sequence on the gold metal contact layer 242. A 400 nm aluminum adhesion reflective layer 252, a 100 nm titanium adhesion reflective layer 253, and a 200 nm gold adhesion reflective layer 254. (6) Performing step 16: for depositing the support substrate 26, first mixing sulfuric acid and hydrogen peroxide in a ratio of 3:1, and putting the test piece which has proceeded to step 15 into the mixed solution, maintaining the temperature at 60QC and soaking for 60 seconds. The purpose is to increase the surface cleanliness and plating adhesion of the attached reflective layer unit 25, and then immerse it in deionized water for 10 minutes, take it out and blow dry. A support substrate 26 made of nickel metal is electroplated on the gold adhesion reflective layer 254 by electroplating. (7) Performing step 17: for removing the conversion substrate 21 and the buffer layer 22, that is, using KrF excimer laser light having a wavelength of 248 nm, which is irradiated from the side of the conversion substrate 21, so that the GaN buffer layer 22 is adjacent to the conversion substrate 21 Nitrogen and gallium are generated by dissociation on one side, and nitrogen is interposed between the buffer layer 22 and the conversion substrate 21 after dissociation, so that the conversion substrate 21 is easily peeled off, and then the test piece is heated to about 11 1293813 30 to 40 ° C. The conversion substrate 21 is peeled off, and the GaN-based epitaxial film composed of the buffer layer 22 and the light-emitting unit 23 is completely positioned on the nickel-metal support substrate 26. Since the laser lift-off method is a conventional technique, it is not detailed. Description. Next, an inductively coupled plasma (ICP) etching is used to remove the GaN buffer layer 22 on the η-GaN second cladding layer 231. Referring to Fig. 5, after the completion of the step 17, the left side is the stripped blue I1 gemstone conversion substrate 21, and the right side is a nickel-plated metal support substrate 26 on which a complete GaN-based epitaxial film remains. Fig. 6 is a photograph of a GaN-based epitaxial film positioned on a nickel metal supporting substrate by a scanning electron microscope (SEM). (8) Performing step 18: for depositing the electrode 27, that is, as shown in FIG. 1, after the chemical solution treatment, the titanium conductive layer 271, the aluminum conductive layer 272, and the titanium conductive layer are sequentially deposited on the second cladding layer 231. 273, and gold conductive layer 274, thereby forming an n-type contact, thus completing the fabrication of the vertical light-emitting two-pole structure of the present invention.
圖7為本發明垂直式LED與傳統橫向LED電流-電壓 特性比較圖，元件尺寸大小皆為300μιηχ300μιη，圖中顯示 本發明在電流為20mA時，順向偏壓為3.01V ;當電流為 80mA時，順向偏壓為3.39V，其順向偏壓較傳統橫向LED /J> ο 綜上所述，本發明分別使用鈦、銘、鈦、金作為附著 反射層251〜254具有下列優點： 12 1293813 (―)所述的鈦附著反射層251與氧的結合力強，故於 〇xidiZed-Ni/Au的金屬接觸層單元24上具有優異的附著力 ，該紹附著反射層252具有高反射率之優點，具有將光反 射的作用，·該鈦附著反射層253層覆蓋於銘附著反射層上 乃2’是作為障壁層（Barrier _γ);而最後覆蓋的金附著反 射層254導電性佳，有利於接觸特性及後續電鑛該奶金屬 支持基板26的製程。 (二） 故本發明藉由該附著反射層單元25之設置，可以 使發光單το 23與支持基板26間有良好的結合附著力，以 利於承受雷射剝離製程的高溫，避免藍寶石轉換基板21在 制離夺仏成GaN基蠢晶薄膜不平整甚至脫離該支持基板％ 的缺失，故可提高製程良率。 (三） 本發明之附著反射層單元25具有光反射的作用， 可以將主動層232產生之部分朝支持基板％行進的光往電 極27方向反射，藉此增加發光二極體的發光效率。 ⑻本發明之附著反射層單元25與金屬接觸層單元24 間，及附著反射層單元25與Ni金屬支持基板％間，皆具 有良好的歐姆接觸’可以有效降低發光二極體的串聯電阻 以及順向偏壓。 惟以上所述者，僅為本發明之較佳實施例而已，當不 能以此限定本發明實施之範圍，即大凡依本發明申請專利 範圍及發明說明内容所作之簡單的等效變化與修飾，皆仍 屬本發明專利涵蓋之範圍内。 【圖式簡單說明】 13 1293813 圖1是本發明垂直式發光二極體（LED)之一較佳實施例 的側視示意圖； 圖2是本發明製造方法之一較佳實施例的流程圖； 圖3是該製造方法在製作發光二極體時，前述發光二 極體的製作過程示意圖； 圖4是一類似圖3的示意圖，顯示一轉換基板及一緩 衝層被移除； 圖5是該較佳實施例在進行雷射剝離製程後，一轉換 基板（左邊），以及一支持基板（右邊）的照片，且於支持基板 上有GaN基磊晶薄膜； 圖6是利用掃描式電子顯微鏡（SEM)拍下圖5中的支持 基板的圖片，圖中顯示支持基板表面的GaN基磊晶薄膜極 為平坦；及 圖7是本發明垂直式LED與傳統橫向LED的電流-電 壓特性比較圖。7 is a comparison diagram of current-voltage characteristics of a vertical LED and a conventional lateral LED according to the present invention, and the element size is 300 μm χ 300 μιη, and the figure shows that the forward bias is 3.01 V when the current is 20 mA; when the current is 80 mA. The forward bias is 3.39V, and its forward bias is higher than that of the conventional lateral LED /J> In summary, the present invention uses titanium, inscription, titanium, and gold as the adhesion reflective layers 251 to 254, respectively, to have the following advantages: 1293813 (-) The titanium adhesion reflective layer 251 has strong bonding force with oxygen, so it has excellent adhesion on the metal contact layer unit 24 of 〇xidiZed-Ni/Au, and the adhesion reflection layer 252 has high reflectance. The advantage is that it has the function of reflecting light. The layer of the titanium adhesion reflective layer 253 is covered on the surface of the reflective layer 2' as the barrier layer (Barrier_γ); and the gold-covered reflective layer 254 finally covered is excellent in conductivity. The process of facilitating the contact characteristics and subsequent electrowinning of the milk metal support substrate 26 is facilitated. (2) Therefore, the present invention can provide a good bonding adhesion between the light-emitting single το 23 and the support substrate 26 by the arrangement of the adhesion reflective layer unit 25, so as to facilitate the high temperature of the laser lift-off process and avoid the sapphire conversion substrate 21. The process yield can be improved by the fact that the GaN-based amorphous film is not flat or even deviated from the support substrate. (3) The adhesion reflection layer unit 25 of the present invention has a function of reflecting light, and the light generated by the active layer 232 toward the support substrate % can be reflected toward the electrode 27, thereby increasing the luminous efficiency of the light-emitting diode. (8) Between the adhesion reflection layer unit 25 of the present invention and the metal contact layer unit 24, and between the adhesion reflection layer unit 25 and the Ni metal support substrate %, both have a good ohmic contact, which can effectively reduce the series resistance and the smoothness of the light-emitting diode. Bias bias. The above is only the preferred embodiment of the present invention, and the scope of the invention is not limited thereto, that is, the simple equivalent changes and modifications made by the scope of the invention and the description of the invention are All remain within the scope of the invention patent. BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a side elevational view of a preferred embodiment of a vertical light emitting diode (LED) of the present invention; FIG. 2 is a flow chart of a preferred embodiment of the manufacturing method of the present invention; 3 is a schematic view showing the manufacturing process of the light-emitting diode in the manufacturing method of the light-emitting diode; FIG. 4 is a schematic view similar to FIG. 3, showing a conversion substrate and a buffer layer being removed; FIG. In the preferred embodiment, after performing the laser stripping process, a conversion substrate (left side) and a support substrate (right side) are photographed, and a GaN-based epitaxial film is formed on the support substrate; FIG. 6 is a scanning electron microscope (FIG. 6) SEM) takes a picture of the support substrate in FIG. 5, which shows that the GaN-based epitaxial film on the surface of the support substrate is extremely flat; and FIG. 7 is a comparison diagram of current-voltage characteristics of the vertical LED of the present invention and the conventional lateral LED.
14 1293813 【主要元件符號說明】 11 〜18 " * »步驟 251 、轉換基板 252 22……" ，緩衝層 253 / ^ <· Κ <· Ν « W Φ Κ 。發光單元 254 231 * ^ * 第二披覆層 26 2 3 2 * * x主動層 27- 2 3 3 * “ ， s第一披覆層 271 2 «Ν«ΧΦ»<·Κ ♦金屬接觸層單元 272 241 <·«***& ，鎳金屬接觸層 273 242 s * ^ *s» s金金屬接觸層 274 25……… -附著反射層單元 s…欽附著反射層 …·紹附著反射層 鈦附著反射層 金附著反射層 ^…支持基板 κ <…電極 。…鈦導電層 ♦…鋁導電層 *…鈦導電層 ，…金導電層14 1293813 [Explanation of main component symbols] 11 to 18 " * »Step 251, conversion substrate 252 22..." , buffer layer 253 / ^ <· Κ <· Ν « W Φ Κ . Light-emitting unit 254 231 * ^ * second cladding layer 26 2 3 2 * * x active layer 27 - 2 3 3 * " , s first cladding layer 271 2 «Ν«ΧΦ»<·Κ ♦ metal contact layer Unit 272 241 <·«***&, nickel metal contact layer 273 242 s * ^ *s» s gold metal contact layer 274 25......... -adhering reflective layer unit s...adhering reflective layer...· 绍 adhesion Reflective layer Titanium adhesion reflective layer Gold adhesion reflective layer ^...Support substrate κ <...electrode....Titanium conductive layer ♦...aluminum conductive layer*...titanium conductive layer,...gold conductive layer
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