200539479 玖、發明說明 【發明所屬之技術領域】 本發明是有關於一種氮化鎵系發光二極體之製作 方法及結構，且特別是一種具有垂直電流方向，以及 高強度光輸出之氮化嫁系發光二極體的製作方法及結 構0 【先前技術】 發光二極體（Light Emitting Diode ; LED)因具有生 產成本低、結構簡單、低耗電、體積小以及安裝容易 之優勢，而大量運用於照明光源以及顯示器技術中。 其中’又以類屬氮化鎵系（Gallium Nitride-based ; GaN-based)的發光元件，例如氮化鎵（GaN)藍光發光二 極體，在近幾年的發光元件市場中，甚受重視。 一般的氮化鎵系發光二極體，基於氮化鎵系膜層 之結晶品質以及成本的考量，大多選用藍寶石 (sapphire)材質作為基板。然而，由於藍寶石係為一絕 緣材料，因此，使得元件中的陽極電極與陰極電極須 面上’而犧牲了部分二極體 不僅減少了元件之實際可發 製作於藍寶石基板的同一 結構之所佔面積，如此， 光面積’ 1導致電流傳送時，無法呈現良好的垂直電 流分佈’而容易於陰極電極附近發生電流擁擠(cu_ crowding)的現象，使操作電咀 电1且^加，以致降低了光輸 出的效率。 200539479 •另外’元件之亮度提升，始終是目前發光二極體 技術的主要發展趨勢，但是，氮化鎵系二極體元件之 發光輸出’除了直接向上射出的部分之外，其他方向 的發光’則會部分被基板吸收，以及朝向元件之邊際 散出’而無法有效地被利用為光輸出的來源。因此， 氮化鎵系發光元件的光輸出強度係完全取決於二極體 本身的發光特性，而使得元件光輸出強度之提升受到 限制。 除此之外，一般的發光二極體結構，通常會在p型 氣化鎵系半導體層上，利用鎳/金（Ni/Au)或鉻/金 (Cr/Au)等金屬材質來製作一電流分散層（current_ spreading layer)，以提升電流分散的效果。然而，由 於透光的需求，以鎳/金或鉻/金等金屬材質製作的電流 分散層厚度，約僅能製作有數百埃（Angstrom ; A)左 右，如此不易形成結構緻密的薄膜品質，反而導致電 流分散的均句性受到影響。同時，以錄/金或鉻/金等金 屬材質製作的電流分散層，具有的光穿透性 (uansmittance)皆低於5〇%，亦會大量侷限了發光二極 體的光輸出強度。 【發明内容】200539479 发明 Description of the invention [Technical field to which the invention belongs] The present invention relates to a method and structure for manufacturing a gallium nitride-based light emitting diode, and more particularly to a nitrided semiconductor having a vertical current direction and high intensity light output. Manufacturing method and structure of light-emitting diodes 0 [Prior technology] Light-emitting diodes (Light Emitting Diodes; LEDs) are widely used because they have the advantages of low production cost, simple structure, low power consumption, small size, and easy installation. In lighting source and display technology. Among them, Gallium Nitride-based (GaN-based) light-emitting devices, such as gallium nitride (GaN) blue light-emitting diodes, have received much attention in the light-emitting device market in recent years. . Generally, GaN-based light-emitting diodes, based on the crystalline quality and cost considerations of GaN-based film layers, mostly use sapphire as the substrate. However, because sapphire is an insulating material, the anode and cathode electrodes in the element must be sacrifice, and some of the diodes are sacrificed, which not only reduces the proportion of the same structure that can actually be produced on the sapphire substrate. Area, so that the light area '1 leads to a failure to present a good vertical current distribution when current is transmitted', which is prone to the phenomenon of current crowding (cu_crowding) near the cathode electrode, which causes the operating nozzle to be electrically charged and increased, thereby reducing the Efficiency of light output. 200539479 • In addition, “the increase in the brightness of components has always been the main development trend of current light-emitting diode technology. However, the light-emitting output of gallium nitride-based diode devices is“ light emission in other directions except for the part directly emitted upwards ”. It will be partially absorbed by the substrate and diffused toward the edge of the element ', and cannot be effectively used as a source of light output. Therefore, the light output intensity of the GaN-based light-emitting device depends entirely on the light-emitting characteristics of the diode itself, so that the improvement of the light output intensity of the device is limited. In addition, the general light-emitting diode structure is usually made of a metal material such as nickel / gold (Ni / Au) or chromium / gold (Cr / Au) on a p-type gallium nitride semiconductor layer. A current spreading layer to improve the effect of current spreading. However, due to the need for light transmission, the thickness of the current dispersion layer made of metal materials such as nickel / gold or chromium / gold can only be about several hundred angstroms (Angstrom; A), so it is not easy to form a dense structured film quality. Instead, the uniformity of current dispersion is affected. At the same time, the current dispersing layer made of metal materials such as recording / gold or chromium / gold has a uansmittance of less than 50%, which will also greatly limit the light output intensity of the light emitting diode. [Summary of the Invention]
之製作方法與結構 (GaN-based)發光二極體 善元件内的電流分散情形， 是在提供一種氮化鎵系 不但可以改 以提升發光二極體的光輸出效 200539479 率更利用7L件結構特性以及元件發光之有效利用，而大 幅增強光輸出的強度，進而提高元件的品質與亮度呈現。 根據本發明之上述目的，提出一種氮化鎵系發光二極 體之製作方法與結構。依照本發明之方法係為先在基板上 依^形成一 η型氮化鎵系半導體層、一主動層以及一 p 型氮化鎵系半導體層。接著，再依序形成一透明導電層與 一反射層，於P型氮化鎵系半導體層之上，其中，透明導 電層係用以作為電流分散層，並同時具有高度光穿透性， 反射層係對於氮化叙系二極體之發光具有高反射率。然 後，形成一導電基材於反射層之上，其中導電基材之形成 則可採用金屬接合技術或是利用導電接著膠之黏合，而將 導電基材之一表面與反射層緊密結合 接著，以雷射剝離或研磨之方式，將基板移除，以完 整暴露出η型氮化鎵系半導體層。最後，再製作第一電極 與第二電極，分別位於η型氮化鎵系半導體層之上，以及 導電基材之另一表面上。其中，更可在第一電極與第二電 極製作之刖，先形成另一透明導電層於η型氮化鎵系半導 體層之上，以提高電流分佈於η型氮化鎵系半導體層中的 均勻性，進而更利於提升元件内部之電流分散效果。 上述之基板一般係為藍寶石基材，而η型氮化鎵系半 導體層以及ρ型氮化鎵系半導體層之材質，則例如為氮化 鎵（GaN)。至於，透明導電層係例如選用銦錫氧化物、銦 辞氧化物或氧化鎳材質。反射層則選用對藍紫綠光具有高 反射特性之金屬材質，例如銀、鋁、鎳、铑或鈀。 200539479 另外’在透明導電層形成步驟之後，可先對透明導電 層與P型氮化鎵系半導體層進行圖形化步驟，以使透明導 電層與p型氮化鎵系半導體層，共同形成具有斜邊之一梯 形結構’再接著進行反射層之形成步驟，使反射層包覆此 梯形結構。如此，反射層亦能佔據元件之部分側邊位置， 而有助於將元件之發光由側邊散射漏失之部分，反射回元 件内，以提高元件實際之光輸出強度。 或者’更可在梯形結構形成之後，反射層形成之前， 先於梯形結構之側邊形成一絕緣保護層，以同時包覆透明 導電層與p型氮化鎵系半導體層之側壁，甚至包覆至主動 層以及η型氮化鎵系半導體層之側壁，使後續形成之反射 層不致接觸到主動層或η型氮化鎵系半導體層，而發生元 件短路的可能，進而達到保護元件電性的效果。其中之絕 緣保護層，係為一絕緣材料層，例如二氧化矽薄膜。 除此之外，在雷射剝離以移除基板之後，亦可先對η 型氮化鎵系半導體層之表面進行微蝕刻，以形成表面粗化 之效果，再進行後續之第一電極與第二電極的製作程序。 或者’也可藉由適當條件之雷射剝離步驟，而於基板移除 時，直接達到η型氮化鎵系半導體層之表面粗化效果。利 用η型氮化鎵系半導體層之表面粗化特性，可減少二極體 發光時，於元件内部所產生之光學全反射現象，進而促使 發光能更有效地予以輸出。 在本發明中，最終係以導電基材來承載氮化鎵系二極 體結構，因此，可將電極直接製作於導電基材上，而有利 200539479 於元件内形成垂直電流分佈，以提高元件内電流傳 的效率，並同時避免電流擁擠的現象產生，進而增月 鎵系元件的光輸出效率。另外，亦不會因電極之‘置虱化 損失元件中氮化鎵系二極體結構的所佔面積，故 高元件之實際可發光面積。 "提The manufacturing method and structure (GaN-based) of the current dispersion in the light-emitting diode device is to provide a gallium nitride system that can not only be modified to improve the light output efficiency of the light-emitting diode, 200539479, but also use a 7L structure. The effective use of the characteristics and light emission of the element, and greatly enhance the intensity of light output, thereby improving the quality and brightness of the element. According to the above object of the present invention, a manufacturing method and structure of a gallium nitride based light emitting diode are proposed. The method according to the present invention is to first form an n-type gallium nitride-based semiconductor layer, an active layer, and a p-type gallium nitride-based semiconductor layer on a substrate. Next, a transparent conductive layer and a reflective layer are sequentially formed on the P-type gallium nitride-based semiconductor layer. The transparent conductive layer is used as a current dispersion layer, and at the same time has a high light transmission and reflection. The layer system has a high reflectivity for the light emission of the nitride series diode. Then, a conductive substrate is formed on the reflective layer, and the conductive substrate can be formed by metal bonding technology or by using a conductive adhesive, and a surface of the conductive substrate is closely combined with the reflective layer to form a conductive substrate. The substrate is removed by laser peeling or grinding to completely expose the n-type GaN-based semiconductor layer. Finally, a first electrode and a second electrode are fabricated on the n-type gallium nitride-based semiconductor layer and on the other surface of the conductive substrate, respectively. Among them, it is possible to form another transparent conductive layer on the n-type gallium nitride-based semiconductor layer before the first electrode and the second electrode are manufactured, so as to increase the current distribution in the n-type gallium nitride-based semiconductor layer. Uniformity, which is more conducive to improving the current dispersion effect inside the device. The above substrate is generally a sapphire substrate, and the material of the n-type gallium nitride-based semiconductor layer and the p-type gallium nitride-based semiconductor layer is, for example, gallium nitride (GaN). The transparent conductive layer is made of, for example, indium tin oxide, indium oxide, or nickel oxide. The reflective layer is made of a metal material with high reflection characteristics for blue-violet-green light, such as silver, aluminum, nickel, rhodium or palladium. 200539479 In addition, after the step of forming the transparent conductive layer, a patterning step may be performed on the transparent conductive layer and the P-type gallium nitride-based semiconductor layer, so that the transparent conductive layer and the p-type gallium nitride-based semiconductor layer together form an inclined One of the sides has a trapezoidal structure, and then a step of forming a reflective layer is performed so that the reflective layer covers the trapezoidal structure. In this way, the reflective layer can also occupy part of the side edge position of the element, which helps to reflect the part of the light emission of the element that is lost by the side edges, and reflects it back into the element to increase the actual light output intensity of the element. Alternatively, 'after the trapezoidal structure is formed and before the reflective layer is formed, an insulating protection layer is formed on the side of the trapezoidal structure to cover the transparent conductive layer and the side wall of the p-type gallium nitride-based semiconductor layer, or even To the sidewalls of the active layer and the n-type gallium nitride-based semiconductor layer, so that the subsequently formed reflective layer does not contact the active layer or the n-type gallium nitride-based semiconductor layer, and the possibility of short-circuiting of the device may occur, thereby achieving electrical protection effect. The insulating protection layer is an insulating material layer, such as a silicon dioxide film. In addition, after the laser is peeled off to remove the substrate, the surface of the n-type GaN-based semiconductor layer can also be micro-etched to form the effect of surface roughening, and then the subsequent first electrodes and first Procedure for making two electrodes. Alternatively, the surface roughening effect of the n-type gallium nitride-based semiconductor layer can be directly achieved when the substrate is removed through a laser peeling step under appropriate conditions. The use of the surface roughening characteristics of the n-type gallium nitride-based semiconductor layer can reduce the optical total reflection phenomenon generated inside the element when the diode emits light, thereby promoting the light emission to be output more effectively. In the present invention, the conductive substrate is used to support the gallium nitride-based diode structure. Therefore, the electrode can be directly fabricated on the conductive substrate, which is beneficial to forming a vertical current distribution in the element in 200539479 to improve the element. The efficiency of current transmission, and at the same time avoid the phenomenon of current crowding, thereby increasing the light output efficiency of the gallium-based elements. In addition, the area occupied by the gallium nitride-based diode structure in the device is not lost due to the lice formation of the electrode, so the actual light-emitting area of the device is high. " mention
同時，本發明更利用反射層與透明導電層之結合，P 同時提高電流分散的效果，並對氮化鎵系元件之發光作^ 效之利用，使氮化鎵系元件之發光向下射出的部分，能大 量穿過透明導電層@傳送至反射層上，再藉由反射層:反 射作用，反射回元件内，使元件之光輸出強度得以大幅增 加’進而提高元件之亮度。 曰 除此之外，本發明中對η型氮化鎵系半導體層表面的 粗化處理，以及對結構堆疊之反射層、透明導電層與ρ 型乳化鎵系半導體層之幾何結構設計，皆亦有助於氮化鎵 系發光元件之光輸出強度的提升。 故藉由本發明之方法所製作的氮化鎵系發光二極 體，不僅增進了元件内部之電流傳遞成效，而有效提升了 元件的光輸出效率，同時，更大幅增加元件之光輸出強度 與可發光面積，因而提高了氮化鎵系發光元件製作之產品 品質與亮度呈現。 【實施方式】 本發明係提供一種氮化鎵系（GaN-based)發光二極體 之製作方法與結構，利用基板轉移之技術，將製作於藍寶 200539479 石基材上的氮化鎵系發光二極體’移轉至導電性基板上， 並且，同時藉由反射層與透明導電層之設置及其幾何結構 設計，以提供元件内良好的垂直電流分佈，以及對元件之 部分發光的有效利用，進而提升電流分散的效果，並提高 元件之光輸出強度。以下將以實施例對本發明之方法加以 詳細說明。 實施例 1 本發明揭露了一種氮化鎵（GaN)發光二極體之製作方 法與結構。依序參照第1A〜1D圖，第1A〜1D圖係為依照 本發明第一實施例之一種氮化鎵發光二極體製作方法的 流程剖面示意圖。 在第1A圖中，首先在基板102上製作氮化鎵二極體 結構’其中，基板102例如選用藍寶石（sapphire)材質， 以獲得結晶品質良好的氮化鎵半導體層，而氮化鎵二極體 結構的製作，係為分別依序形成一 n型氮化鎵半導體層 104 具有多層置子井（Multi-Quantum Well)結構之發光 主動層106，以及一 P型氮化鎵半導體層108於基板1〇2 之上。 接著，在P型氮化鎵半導體層108之上，形成一透明 導電層U〇，以作為電流分散層（current-spreading ―)’提供電流分散作用，並具有良好之歐姆接觸特性 以及光穿透特性，同時，读 τ遗明導電層no亦可當作ρ型氮 化錄半導體層108斑及私 /、夂射層112之間的緩衝層。透明導電 200539479 層110的材質例如可為銦錫氧化物（Indium Tin Oxide; ITO)、銦鋅氧化物（Indium-Zinc Oxide ; IZO)或氧化鎳 (nickel oxide ; NiO)，擁有大於90%的光穿透性，可使 發光二極體結構所產生的光大量穿透。然後，在透明導 電層110之上，形成一金屬反射層112，對於紫藍綠光波 長範圍之發光具有高反射率，反射層112選用的材質，例 如可為銀（Ag)、鋁（A1)、鎳（Ni)、铑（Rh)或鈀（Pd)等具有高 反射率之金屬材質。 其中’利用透明導電層11 〇的氧化物材質特性，可與 反射層112之金屬形成金屬氧化層的結合反應，而使透明 導電層110與反射層112之接合強度提升，以形成良好之 薄膜接合品質。 在反射層112形成之後，於反射層112的表面製作一 金屬接合層113,以與一導電基材116上的金屬接合層114 相接觸，藉由金屬接合（metal b〇nding)的方式，使導電基 材116形成於反射層112之上方，與製作於基板1〇2上的 氮化鎵結構相結合。其中，金屬接合層113的材質例如可 為鎳、金（Au)、銅（Cu)、鈀、銦（In)或錫（Sn)，而金屬接 合層114的材質則例如可為錄、金、銅、纪、氮化鈕（TaN) 或鼠化鈦⑽）。金屬接合層113與金屬接合層ιΐ4係以 金屬鍵t的型式進仃接合，而達到將導電基材η 6連接於 反射層112之上的目的。另外，導電基材ιΐ6係選用具有 導電性的材質，例如可氧功,c u』為矽（Si)、銅、砷化鎵（GaAs)或其 他金屬，甚至是金屬合金。 一 12 200539479 用古-+ /于、了上述之金屬接合的方式之外，亦可直接使 層ml、、、機之導電接著膠’將導電基材116黏合於反射 曰 之上，又或者利用金屬電鍍的技術，於反射層112 接形成-導電金屬層以作為導電基材116。 。在+導電基材116連接至反射層112之後，參照第1Β 圖接著，進行一雷射剝離（iaser lift 〇ff)製程，利用一適 當條件之雷射来φ2 n , ^ t ^ ^ 九束13〇，由基板1〇2之背面予以照射，使At the same time, the present invention makes more use of the combination of the reflective layer and the transparent conductive layer, and at the same time improves the effect of current dispersion, and makes use of the light emission of the gallium nitride device, so that the light emission of the gallium nitride device is emitted downward. In part, it can be transmitted through the transparent conductive layer @ to the reflective layer in large quantities, and then reflected back to the element by the reflective layer: the reflection effect, so that the light output intensity of the element can be greatly increased, thereby improving the brightness of the element. In addition, in the present invention, the roughening treatment of the surface of the n-type gallium nitride-based semiconductor layer, and the geometrical design of the reflective layer, the transparent conductive layer, and the p-type emulsified gallium-based semiconductor layer in the structure stack are also applicable. Contributes to the improvement of light output intensity of GaN-based light-emitting devices. Therefore, the gallium nitride-based light-emitting diode manufactured by the method of the present invention not only improves the current transmission effect inside the element, but also effectively improves the light output efficiency of the element, and at the same time, greatly increases the light output intensity and the light output of the element. The light-emitting area improves the quality and brightness of products made of gallium nitride-based light-emitting devices. [Embodiment] The present invention provides a manufacturing method and structure of a gallium nitride (GaN-based) light-emitting diode. Using a substrate transfer technology, a gallium nitride-based light-emitting diode fabricated on a sapphire 200539479 stone substrate will be used. The body 'is transferred to the conductive substrate, and at the same time, the arrangement of the reflective layer and the transparent conductive layer and the design of the geometric structure thereof are used to provide a good vertical current distribution in the element and an effective use of part of the light emission of the element. Improve the effect of current dispersion and increase the light output intensity of the device. Hereinafter, the method of the present invention will be described in detail with examples. Embodiment 1 The present invention discloses a manufacturing method and structure of a gallium nitride (GaN) light emitting diode. Figures 1A to 1D are sequentially referred to, and Figures 1A to 1D are schematic cross-sectional views showing the flow of a method for manufacturing a gallium nitride light emitting diode according to the first embodiment of the present invention. In FIG. 1A, a gallium nitride diode structure is first fabricated on a substrate 102. Among them, the substrate 102 is made of sapphire, for example, to obtain a gallium nitride semiconductor layer with good crystal quality, and the gallium nitride diode The fabrication of the bulk structure is to sequentially form an n-type gallium nitride semiconductor layer 104, a light-emitting active layer 106 with a multi-quantum well structure, and a p-type gallium nitride semiconductor layer 108 on the substrate. 1〇2. Next, a transparent conductive layer U0 is formed on the P-type gallium nitride semiconductor layer 108 as a current-spreading layer to provide a current-spreading effect, and has good ohmic contact characteristics and light penetration. At the same time, it can be seen that the conductive layer no can also be used as a buffer layer between the p-type nitride recording semiconductor layer 108 and the private / radiation layer 112. The material of the transparent conductive 200539479 layer 110 may be, for example, Indium Tin Oxide (ITO), Indium-Zinc Oxide (IZO), or Nickel Oxide (NiO), and has more than 90% light The penetrability allows a large amount of light generated by the light emitting diode structure to pass through. Then, a metal reflective layer 112 is formed on the transparent conductive layer 110, and has a high reflectance for the emission of the purple, blue, and green wavelength ranges. The material selected for the reflective layer 112 may be, for example, silver (Ag), aluminum (A1) , Nickel (Ni), rhodium (Rh) or palladium (Pd) and other metal materials with high reflectivity. Among them, the use of the characteristics of the oxide material of the transparent conductive layer 110 can form a combination reaction with the metal of the reflective layer 112 to form a metal oxide layer, so that the bonding strength of the transparent conductive layer 110 and the reflective layer 112 is improved to form a good thin film joint. quality. After the reflective layer 112 is formed, a metal bonding layer 113 is formed on the surface of the reflective layer 112, and it is in contact with the metal bonding layer 114 on a conductive substrate 116, and the metal bonding is performed by means of metal bonding. The conductive substrate 116 is formed above the reflective layer 112 and is combined with a gallium nitride structure fabricated on the substrate 102. The material of the metal bonding layer 113 may be, for example, nickel, gold (Au), copper (Cu), palladium, indium (In), or tin (Sn), and the material of the metal bonding layer 114 may be, for example, aluminum, gold, Copper, copper, titanium nitride (TaN), or titanium hafnium). The metal bonding layer 113 and the metal bonding layer ι4 are bonded by a type of a metal bond t, so as to connect the conductive substrate η6 to the reflective layer 112. In addition, the conductive substrate ιΐ6 is made of conductive materials, such as oxygen work, and c u ′ is silicon (Si), copper, gallium arsenide (GaAs) or other metals, and even metal alloys. 12 200539479 In addition to the above-mentioned metal bonding method, the conductive layer 116 can be directly bonded to the conductive substrate 116 on the reflective substrate, or it can be used. In the metal plating technology, a conductive metal layer is formed on the reflective layer 112 as a conductive substrate 116. . After the + conductive substrate 116 is connected to the reflective layer 112, referring to FIG. 1B, a laser lift (iaser lift) process is performed, and a laser with an appropriate condition is used to φ2 n, ^ t ^ ^ nine beams 13 〇, irradiate from the back of the substrate 102
田射光束130穿透基板，並被n型氮化錄半導體層刚 所吸收，以分離基板1〇2與η型氮化鎵半導體層，而 將基板102移除。如第！ c圖所示，完成氮化錄結構之基 材轉移的目的。另外，基板i 〇2之移除亦可採用研磨技 術，直接將基板1 〇2磨除，而暴露出n型氮化鎵半導體層 104。The field beam 130 penetrates the substrate and is absorbed by the n-type nitride semiconductor layer to separate the substrate 102 from the n-type gallium nitride semiconductor layer and remove the substrate 102. As the first! As shown in Figure c, the purpose of transferring the substrate of the nitrided structure is completed. In addition, the substrate i 〇2 can also be removed by using a polishing technique to directly remove the substrate 102 and expose the n-type gallium nitride semiconductor layer 104.
在第1C圖中，氮化鎵結構係為一下方p型之二極體 結構，p型氮化鎵半導體層1〇8位於η型氮化鎵半導體層 104之下方，且承載基材為具有導電性的導電基材116。 其中，本實施例更將η型氮化鎵半導體層1〇4，形成表面 粗化（surface roughening)之效果，較佳例如可使η型氮化 鎵半導體層104之表面產生尺寸約為〇·5//ηι的凹槽。利 用η型氮化鎵半導體層1〇4表面的高低起伏，以減少氮化 鎵二極體之發光向上射出時，於元件内部產生之部分光學 全反射現象，進而促使發光能更有效地予以輸出。 使η型氮化鎵半導體層104形成表面粗化之方法，可 利用微蝕刻的技術進行，例如使用感應耦合電漿式 13 200539479 (Inductively Coupled Plasma ; ICP)蝕刻或光輔助化學式 (Photo-Enhanced Chemical; PEC)蝕刻，對 n 型氮化鎵半 導體層104表面進行微量的蝕刻作用，以產生高粗糙度之 表面特性。另外，或是可直接利用雷射剝離製程，使基板 102移除之後，能同時達到n型氮化鎵半導體層1〇4之表 面粗化特性。 最後，參照弟1D圖，再形成一透明導電層12 〇於η 型氮化鎵半導體層104之上，並依序分別製造陰極電極 122於透明導電層120之上，以及陽極電極124於導電基 材116之下方表面上，而完成一完整之氮化鎵發光元件。 其中，透明導電層120係同樣例如選用銦錫氧化物、 銦鋅氧化物或氧化鎳，以同時提高η型氮化鎵半導體層 104中的電流分散效果，以及電流分佈之均勻性，而有利 於提升元件之發光效率與元件亮度之均勻呈現，進而可良 好運用在大面積之氮化鎵發光二極體的製作上。 另外，由於利用導電基材116具有之導電特性，故可 直接將陽極電極124製作於導電基材116之下方，使氮化 鎵發光元件内的電流傳送呈現垂直電流之方向分佈，避免 電流擁擠的現象，以提高電流分散之成效；同時，亦不會 因電極124之裝設位置，而犧牲部分之可發光面積，進而 有效提升元件之光輸出效率，以及增加實際之發光面積。 在第一實施例中，利用具有高反射特性之反射層的設 置’可使元件内的發光，除了 一部份直接向上輸出之外， 另一部份向下發出的光，則藉由反射層的反射作用，而提 14 200539479 仏成為向上輸出的光源，使元件内的發光能被有效地利 用，以增加元件可達成的光輸出強度。 另外’更在P型氮化鎵半導體層與反射層之間，設置 透明導電層，以作為電流分散層，除了提供電流分散作 用以及具有良好之歐姆接觸特性之外，有助於電流由p 型氮化鎵半導體層順利地傳遞至η型氮化鎵半導體層，同 時，亦能藉由透明導電層之高度光穿透特性，而使氮化鎵 70件内之發光，可大量穿透透明導電層，進而傳送至反射 層上，供反射層進行光反射，使增加元件實際可擷取的反 射光量，有利於光輸出強度之提升。 除此之外’本實施例亦利用η型氮化鎵半導體層之表 面粗化的形成，以減少元件内氮化鎵二極體發光之光學全 反射現象，而使光輸出強度增加。 實施例2 本發明揭露了另一種氮化鎵（GaN)發光二極體之製作 方法與結構。依序參照第2A〜2D圖，第2A〜2D圖係為依 照本發明第二實施例之一種氮化鎵發光二極體製作方法 的流程剖面示意圖。 在第2A圖中，如同第一實施例，先在基板202上， 分別依序形成一 η型氮化鎵半導體層2〇4, 一具有多層量 子井結構之發光主動層206，以及一 ρ型氮化蘇半導體層 208於基板202之上，接著，再形成一透明導電層21〇。 其中，基板202的材質例如可為藍寶石，而透明導電層 15 200539479 1 〇的材吳則例如選用銦錫氧化物、銦鋅氧化物或氧 錄’以：為電流分散層，並同時具有高度之光穿透特性。 ,與第實施例不同的是，在透明導電層210形成之 同夺對Ρ型氮化鎵半導體層208以及透明導電屑 ，進行圖案化步驟，以㈣方式定義出—梯形結構: 而使Ρ型氮化鎵半導體層2〇8與透明導電層21〇,產生具 有斜度（taper)之側面斜邊。 、 接著，形成一絕緣保護層2〇9,以同時包覆透明導電 層210與p型氮化嫁半導體層2〇8之側壁，甚至包覆至主 動曰206以及n型氮化錄半導體層2〇4之側壁，以隔絕結 構側壁之電性。其中之絕緣保護層2〇9,係為一絕緣材二 層，例如一氧化石夕（Si 〇2)薄膜。 然後，參照第2B圖，形成一反射層212，覆 型氮化鎵半導體層，以及透明導電層21〇所構成之梯 構上，、中，反射層2 12係選用對紫藍綠光波長範圍 之發光具有高反射率的金屬材質，例如可為銀、銘、錄、 姥或Ιε。 ' 由於梯形結構之設計，容易使具導電性之反射声 ⑴，接觸到主㈣2(^η型氮化鎵半導體層⑽，而 造成元件短路而影響電性表現。故藉由絕緣之保護層 的設置’可使後續形成之反射層212不致接觸到主^ 層梅或⑭氮化鎵半導體& 2〇4，進而達到保言蔓元件 性的效果。 接著，再於反射層212的表面製作一金屬接合層 16 200539479 2 13 ’如同第一實施例的方式，以與另一導電基材2丨6上 的金屬接合層2 14相接觸，使導電基材2 1 6形成於反射層 212之上方，與製作於基板2〇2上的氮化鎵結構相結合。 導電基材216係選用具有導電性的材質，同樣例如可為 石夕、銅、砷化鎵或其他金屬，甚至是金屬合金。 在導電基材216連接至反射層212之後，即採用如同 第一實施例中的基板轉移方法，以移除基板202，形成如 第2 C圖所示的結構。 在第2 C圖中’氮化嫁結構係為一下方p型之二極體 結構’且承載基材為具有導電性的導電基材2 1 6。另外， 亦同樣採用第一實施例的方法，以蝕刻方法或是利用雷射 剝離製程，使η型氮化鎵半導體層2〇4，形成表面粗化的 效果，例如可使η型氮化鎵半導體層2〇4之表面產生尺寸 約為0.5// m的凹槽，以減少氮化鎵二極體内的光學全反 射現象’而使氮化鎵結構之發光更有效地輸出，進而提升 元件之光輸出強度。 另外，由於在第二實施例中，利用p型氮化鎵半導 體層208以及與其連接之透明導電層21〇的梯形結構設 計，而使反射層212於元件中所形成的位置，除了於透明 導電層210之下方以外，更佔據氮化鎵元件内之部分側邊 位置，以使元件内向側邊散射之發光，亦能藉由反射層 212的反射作用，而反射回元件内，提供為元件之光輸出 來源，以減少氮化鎵發光元件於側邊散出之光損失，進而 更增進元件之光輸出強度。 17 200539479 最後，參照第2D圖，再形成另一透明導電層22〇於 η型氮化鎵半導體層綱之上，並依序分別製造陰極電極 222於透明導電層220之上，以及陽極電極224於導電基 材216之上，而完成一完整之氮化鎵發光元件。 因此，根據上述，第二實施例除了具有與第一實 施例相同的優點之外，更因？型氮化鎵半導層，以及與 其相連之透明導電層的梯形結構設計，而將元件内之發光 作更有效地利用，使朝向元件下方射出或由元件側邊散出 之光源部分，皆能用以提升元件之光輸出強度，使元件之 亮度大幅增加。 根據本發明之上述實施例可知，應用本發明之氮化鎵 發光二極體的製作方法，可將原本的絕緣性基板，轉換為 導電性基板，使電極可製作於導電性基板之下方，以利於 元件内形成垂直電流分佈，而提高元件内電流傳遞分散的 效率，並同時避免電流擁擠的現象產生，進而增進氮化鎵 元件的光輸出效率。另外，氮化鎵二極體之實際可發光面 積，亦因電極設置位置的影響，而獲得有效地提升。 另外，本發明更利用反射層與透明導電層之結合，與 Ρ型氮化鎵半導體層結構相連接，以同時提高電流分散的 效果，以及對氮化鎵元件之發光的有效利用，使氮化鎵元 件的光輸出強度得以大幅增加，進而提高元件之亮度呈 現。 除此之外，本發明中對η型氮化鎵半導體層表面的粗 化處理，以及對結構堆疊之反射層、透明導電層與Ρ型氮 18 200539479 化鎵半導體層之幾何結構設計，皆有助於氮化鎵元件之光 輸出強度的提升。 本發明不只侷限於使用在氮化鎵發光二極體的技術 上’其他所有屬於氮化鎵系發光二極體元件之製作，例如 氮化銦鎵（InGaN)發光二極體或氮化鋁鎵（A1GaN)紫外光 發光二極體，亦可藉由本發明之方法製作，而大幅提升產 品的特性。 雖然本發明已以實施例揭露如上，然其並非用以限 疋本發明，任何熟習此技藝者，在不脫離本發明之精神和 範圍内，當可作各種之更動與修飾，因此本發明之保護範 圍當視後附之申請專利範圍所界定者為準。 巳 【圖式簡單說明】. ▲為讓本發明之上述特徵、方法、目的及優點能更明顯 易懂，配合所附圖式，加以說明如下· 第1A〜1 D圖係為依照本發明一 嫂菸氺—托挪制仏 弟一貫施例之一種氮化 ㈣先-極體製作方法的流程剖面示意圖；以及 第2A〜2D圖係為依照本發明第二實施例 鎵發光二極體製作方法的流程剖面示意圖。 亂化 【元件代表符號簡單說明】 102、202 :基板 t A鎵半導體層 104 、 1〇8 、 204 、 208 106、206 :主動層 19 200539479 110、120、210、220 ··透明導電層 112、 2 1 2 ··反射層 113、 114、213、214:金屬接合層 116、216 :導電基材 122、124、222、224 ··電極 130 :雷射光束 209 :保護層In FIG. 1C, the gallium nitride structure is a lower p-type diode structure, and the p-type gallium nitride semiconductor layer 108 is located below the n-type gallium nitride semiconductor layer 104. A conductive conductive substrate 116. Wherein, in this embodiment, the n-type gallium nitride semiconductor layer 104 is formed to have a surface roughening effect. Preferably, for example, the surface of the n-type gallium nitride semiconductor layer 104 can have a size of about 0 ·. 5 // ηι groove. Use the undulations on the surface of the n-type GaN semiconductor layer 104 to reduce the part of the total optical reflection generated inside the element when the light emission of the gallium nitride diode is emitted upward, thereby promoting the light to be output more effectively. . The method for roughening the surface of the n-type gallium nitride semiconductor layer 104 can be performed by using a micro-etching technique, for example, using inductively coupled plasma (ICP) 13 200539479 (ICP) etching or Photo-Enhanced Chemical PEC) etching, which performs a small amount of etching on the surface of the n-type gallium nitride semiconductor layer 104 to produce a surface characteristic with high roughness. In addition, the laser stripping process may be used directly, so that after the substrate 102 is removed, the surface roughening characteristics of the n-type gallium nitride semiconductor layer 104 can be achieved at the same time. Finally, referring to FIG. 1D, a transparent conductive layer 120 is formed on the n-type gallium nitride semiconductor layer 104, and a cathode electrode 122 on the transparent conductive layer 120 and an anode electrode 124 on the conductive substrate are sequentially manufactured respectively. The lower surface of the material 116 completes a complete gallium nitride light emitting device. Among them, the transparent conductive layer 120 is also selected from, for example, indium tin oxide, indium zinc oxide, or nickel oxide, to simultaneously improve the current dispersion effect in the n-type gallium nitride semiconductor layer 104 and the uniformity of the current distribution, which is beneficial to the Improve the luminous efficiency of the device and the uniform display of the brightness of the device, which can be well used in the production of large area GaN light emitting diodes. In addition, due to the use of the conductive characteristics of the conductive substrate 116, the anode electrode 124 can be fabricated directly below the conductive substrate 116, so that the current transmission in the gallium nitride light-emitting element is distributed in the direction of the vertical current to avoid current crowding. Phenomenon to improve the effectiveness of current dispersion; at the same time, it will not sacrifice the light-emitting area of the part due to the installation position of the electrode 124, thereby effectively improving the light output efficiency of the device and increasing the actual light-emitting area. In the first embodiment, the use of the arrangement of a reflective layer having a high reflection characteristic allows light emission in the element, in addition to a portion of the light output directly upwards, and another portion of the light emitted downwards through the reflective layer 14 200539479 提 becomes a light source with upward output, so that the light emission in the element can be effectively used to increase the light output intensity that the element can achieve. In addition, a transparent conductive layer is provided between the P-type gallium nitride semiconductor layer and the reflective layer as a current dispersing layer. In addition to providing a current dispersing effect and having good ohmic contact characteristics, it also helps current flow from the p-type The gallium nitride semiconductor layer is smoothly transferred to the n-type gallium nitride semiconductor layer. At the same time, the high light transmission characteristics of the transparent conductive layer can make the light emission in 70 gallium nitride layers, which can penetrate a large number of transparent conductive layers. Layer, and then transmitted to the reflective layer for the reflective layer to reflect light, so that the amount of reflected light that can be actually captured by the element is increased, which is beneficial to the improvement of light output intensity. In addition, this embodiment also uses the formation of a roughened surface of the n-type gallium nitride semiconductor layer to reduce the optical total reflection phenomenon of the gallium nitride diode light emission in the element, thereby increasing the light output intensity. Embodiment 2 The present invention discloses another manufacturing method and structure of a gallium nitride (GaN) light emitting diode. 2A to 2D are sequentially referred to, and the 2A to 2D diagrams are schematic cross-sectional views of a process for manufacturing a gallium nitride light emitting diode according to a second embodiment of the present invention. In FIG. 2A, as in the first embodiment, an n-type gallium nitride semiconductor layer 204, a light-emitting active layer 206 having a multilayer quantum well structure, and a p-type are sequentially formed on the substrate 202, respectively. A thallium nitride semiconductor layer 208 is formed on the substrate 202, and then a transparent conductive layer 21 is formed. Wherein, the material of the substrate 202 may be sapphire, and the material of the transparent conductive layer 15 200539479 1 0 is, for example, indium tin oxide, indium zinc oxide, or oxygen, which is used as a current dispersion layer and has a high degree of Light transmission characteristics. The difference from the first embodiment is that the P-type gallium nitride semiconductor layer 208 and the transparent conductive chips are formed on the transparent conductive layer 210, and a patterning step is performed to define a trapezoidal structure in a ㈣ manner: The gallium nitride semiconductor layer 208 and the transparent conductive layer 21 generate a beveled side surface having a taper. Then, an insulating protection layer 209 is formed to cover the sidewalls of the transparent conductive layer 210 and the p-type nitrided semiconductor layer 208 at the same time, and even to the active layer 206 and the n-type nitrided semiconductor layer 2 〇4 side wall to isolate the electrical properties of the structure side wall. Among them, the insulating protection layer 209 is an insulating material and two layers, such as a SiO 2 film. Then, referring to FIG. 2B, a reflective layer 212, an overlying gallium nitride semiconductor layer, and a transparent conductive layer 21 are formed on the ladder structure. The middle, middle, and reflective layers 2 and 12 are selected for the wavelength range of purple blue green light. The metal material that emits light with a high reflectivity can be, for example, silver, inscriptions, recordings, osmium, or Iε. '' Due to the design of the trapezoidal structure, it is easy to make the conductive reflection sound ⑴ contact the main ㈣2 (^ η-type gallium nitride semiconductor layer ⑽), which causes the element to short-circuit and affect the electrical performance. Therefore, the insulating protective layer The setting “can prevent the subsequently formed reflective layer 212 from contacting the main layer or ytterbium gallium nitride semiconductor & 204, so as to achieve the effect of guaranteeing element properties. Next, a surface of the reflective layer 212 is fabricated. Metal bonding layer 16 200539479 2 13 'As in the first embodiment, in contact with the metal bonding layer 2 14 on another conductive substrate 2 丨 6, the conductive substrate 2 1 6 is formed above the reflective layer 212. And combined with a gallium nitride structure fabricated on the substrate 202. The conductive substrate 216 is made of a conductive material, and can also be, for example, Shi Xi, copper, gallium arsenide or other metals, or even metal alloys. After the conductive substrate 216 is connected to the reflective layer 212, the substrate transfer method as in the first embodiment is used to remove the substrate 202 to form a structure as shown in FIG. 2C. In FIG. 2C, 'nitrogen The marrying structure is a p-type The polar body structure and the carrier substrate is a conductive substrate 2 1 6 having conductivity. In addition, the method of the first embodiment is also used to make the n-type gallium nitride semiconductor by the etching method or the laser lift-off process. Layer 204, which has the effect of roughening the surface. For example, a groove having a size of about 0.5 // m can be generated on the surface of the n-type gallium nitride semiconductor layer 204 to reduce the optical volume in the gallium nitride diode. The total reflection phenomenon causes the light emission of the gallium nitride structure to be output more effectively, thereby increasing the light output intensity of the device. In addition, in the second embodiment, the p-type gallium nitride semiconductor layer 208 and the transparent conductive material connected to it are used. The trapezoidal structure of the layer 21 is designed so that the position where the reflective layer 212 is formed in the element, besides the transparent conductive layer 210, also occupies a part of the side position of the gallium nitride element, so that the element faces inward. Scattered light can also be reflected back into the element through the reflection of the reflective layer 212 to provide the light output source of the element, so as to reduce the loss of light emitted by the gallium nitride light-emitting element on the side, thereby further improving the element. 17 200539479 Finally, referring to FIG. 2D, another transparent conductive layer 22 is formed on the n-type gallium nitride semiconductor layer, and a cathode electrode 222 is sequentially fabricated on the transparent conductive layer 220, respectively. And the anode electrode 224 is on the conductive substrate 216 to complete a complete gallium nitride light-emitting element. Therefore, according to the above, the second embodiment has the same advantages as the first embodiment, but also a? The gallium nitride semiconducting layer and the trapezoidal structure design of the transparent conductive layer connected to it make more effective use of the light emission in the element, so that the light source part that is emitted below the element or scattered from the side of the element can be used. In order to increase the light output intensity of the component, the brightness of the component is greatly increased. According to the above-mentioned embodiments of the present invention, it can be known that by applying the manufacturing method of the gallium nitride light-emitting diode of the present invention, the original insulating substrate can be converted into a conductive substrate, so that the electrode can be fabricated under the conductive substrate to It is conducive to forming a vertical current distribution in the element, and improves the efficiency of current transfer and dispersion in the element, and at the same time avoids the phenomenon of current crowding, thereby improving the light output efficiency of the gallium nitride element. In addition, the actual light-emitting area of the gallium nitride diode is effectively improved due to the influence of the position of the electrode. In addition, the present invention uses a combination of a reflective layer and a transparent conductive layer to connect with a P-type gallium nitride semiconductor layer structure to simultaneously improve the effect of current dispersion and the effective use of the light emission of a gallium nitride element to make the nitride The light output intensity of the gallium element can be greatly increased, thereby improving the brightness appearance of the element. In addition, in the present invention, the roughening treatment of the surface of the n-type gallium nitride semiconductor layer, and the geometric structure design of the reflective layer, the transparent conductive layer, and the p-type nitrogen 18 200539479 gallium semiconductor layer of the structure stack are all provided. Helps improve the light output intensity of gallium nitride devices. The invention is not limited to the use of GaN light-emitting diodes. All other GaN-based light-emitting diode devices are manufactured, such as indium gallium nitride (InGaN) light-emitting diodes or aluminum gallium nitride. (A1GaN) ultraviolet light-emitting diodes can also be produced by the method of the present invention, which greatly improves the characteristics of the product. Although the present invention has been disclosed as above by way of examples, it is not intended to limit the present invention. Any person skilled in the art can make various changes and modifications without departing from the spirit and scope of the present invention. The scope of protection shall be determined by the scope of the attached patent application.巳 [Brief description of the drawings]. ▲ In order to make the above-mentioned features, methods, objects, and advantages of the present invention more obvious and easy to understand, the following descriptions are given in conjunction with the attached drawings. Figures 1A ~ 1D are according to the present invention.嫂 烟 氺 —Tuo Nuo's conventional example of a method of manufacturing a nitride nitride precursor-polar body process flow diagram; and Figures 2A to 2D are manufacturing methods of gallium light-emitting diodes according to the second embodiment of the present invention Process flow diagram. Chaos [simple description of element representative symbols] 102, 202: substrate t A gallium semiconductor layer 104, 108, 204, 208 106, 206: active layer 19 200539479 110, 120, 210, 220 ·· transparent conductive layer 112, 2 1 2 · Reflective layers 113, 114, 213, 214: Metal bonding layers 116, 216: Conductive substrates 122, 124, 222, 224 · Electrode 130: Laser beam 209: Protective layer
2020