A7 B7 4 633 9 5 6964twfdoc/0〇8 五、發明說明（（） 本發明是有關於一種發光二極體之結構，且特別是 有關於一種具有網狀歐姆接觸層的高亮度發光二極體結 構。 現今的發光二極體製作漸趨成熟，故可以做成具有 高信賴度的大型顯示看板。由於大型的顯示看板所採用的 發光二極體必須具備高亮度的特性，以使其大型的顯示看 板不僅是大而淸晰，更能夠在遠距離觀看其顯示的內容。 因此發光二極體的發展始終朝著高亮度、低耗電率的方向 前進。 發光二極體的主要材質磷化鋁鎵銦(AlGalnP)爲一直 接能隙材料，在與砷化鎵(GaAs)晶格匹配的條件下，適當 調整鋁與鎵的比例可調變發光的波長介於550nm-680nm 之間’約爲綠光至紅光的波長範圍。由於增加鋁的含量可 以增大材料的能隙，故一般會以鋁含量高的磷化鋁鎵銦作 爲侷限層（Confining Layer )夾住中心的載子發光層或稱活 性層（Active Layer )，以提高載子的注入效率，進而形成 高發光效率的雙異質結構（Double Hetero-structure )發光 二極體。其中，由於侷限層的能隙較所發出之光子的能量 大’故侷限層並不會吸收由活性層所發出的光。 首先請先參照第1圖，一般磷化鋁鎵銦發光二極體 是以有機金屬化學氣相沉積（Metal Organic Chemical Vapor Deposition，MOCVD )的方式於n型砷化鎵基板100上依 序成長一 η型磷化鋁鎵銦侷限層102、一磷化鋁鎵銦活性 層104、一 ρ型磷化鋁鎵銦侷限層1〇6，最後再蒸鍍上一 3 本紙張尺度適用中國國家標準（CNS)A4規格（210 X 297公釐） <請先閲讀背面之注意事項再填寫本頁) -rw-------丨訂—I—!線· 經濟部智慧財產局員工消費合作社印製 經濟部智慧財產局員工消費合作社印製 463395 A7 6964twf.d〇c/008 37 五、發明說明（V) 正面電極108及背面電極110即完成一發光二極體元件的 製作。而爲了提高正面整體的發光強度，通常會再加上布 拉格反射鏡層 112( Distributed Bragg Reflector )於 η 型磷 化鋁鎵銦侷限層102之下方，如此便可以將射往η型砷化 鎵基板100的光子反射回正面輸出。由於Ρ型磷化鋁鎵銦 材料在磊晶上有移動率過低及摻雜高濃度不易的問題，會 使得其電阻係數偏高（約〇.5D-cm)以致於橫向電流無法 有效地分散到整個晶粒上，由於載子大部份僅注入於正面 電極108的正下方，故其他位置的活性層104便無法獲得 足夠載子進行復合發光。再者，此種電流擁擠現象（ Current Crowding )亦會造成大部分產生的光被不透光的正面電極 108擋住而反射回半導體本體（Bulk )或被吸光的基板100 所吸收，造成元件的發光效率大幅降低。 接著請參照第2圖，爲了解決上述之缺點而在第1 圖結構中的p型磷化鋁鎵銦侷限層106及正面電極108之 間加入一電流分散層114( Current-Spreading Layer )’此電 流分散層114除了對活性層104所發出的光具極佳的穿透 性外，更重要的是它比磷化鋁鎵銦可摻雜較高的濃度且具 較高的移動率，故電流分散層114具有較低的電阻係數， 可使整個晶粒獲得較均勻的電流，目前電流分散層114採 用的材料以砷化鋁鎵（AlGaAs )及磷化鎵（GaP )爲主。然 而上述所提到的電流分散層114 一般都需數十微米厚才能 達到足夠大的電流分散能力，但賴以成長電流分散層114 的有機金屬化學氣相沉積_( MOCVD )其成長速率相當的緩 4 本紙張尺度適用中國國家標準（CNS)A4規格（2Κ) X 297公釐） (請先閲讀背面之注意事項再填寫本頁) t— ϋ ϋ ——訂-------線-C3·- B7 446339 5 6964twfdoc/008 五、發明說明（、） 慢，使得元件的製造成本提高及製造時間增長。 接著請參照第3圖’爲了解決電流分散層114成長速 率太慢的問題，因此以一透光導電氧化物層116作爲發光 二極體的電流分散層，此導電氧化物不但具有良好的光穿 透性，且具有極低的電阻係數（約3xl(V4n_cm；)，故可有 效的將電流分散於整個晶粒’進而提高發光二極體的發光 效率，一般當作此透光導電層的適當材料有氧化銦、氧化 錫及氧化銦鍚。爲了使此透光導電氧化物與半導體間形成 良好的歐姆接觸並增加此透光導電氧化物於半導體上的附 著力’通常會在形成此透光導電氧化物之前，先成長一層 高摻雜的p型歐姆接觸層118。其中，歐姆接觸層厚 度一般需大於500A，且濃度需大於1018cnr3，而歐姆接觸 層118的材料有砷化鎵 '磷化鎵，或是磷砷化鎵（GaAsP ) 等晶格常數相差不大且具有窄能隙的材料。而在形成導電 氧化層作爲電流分散層116前，成長p型歐姆接觸層ι18 的確有其必要性，但由於歐姆接觸層118的能隙較活性層 104者小，會對二極體發出的光進行再吸收而使得整體亮 度大大降低。 接著請參照第4圖，其繪示爲不同材料在不同波長. 時的光吸收係數分佈圖。由第4圖中可以得知不同化合物 如砷化鱗鎵銦（GainAsP )、砷化鎵（GaAs )、磷化銦（inp )、 鍺（Ge )、磷化鎵（GaP )、矽（Si )等材質在絕對溫度3〇〇κ 時的光吸收係數α對應於光波長λ的分佈圖》 因此，本發明的目的在提出一種發光二極體之結構， 5 !_ —丨丨丨丨丨^,1、敦ill!訂*!·線 (請先閱讀背面之注意事項再填窝本頁) 經濟部智慧財產局員工消費合作社印製 本紙張尺度適用中國國家標準（CNS)A4規格⑽χ 297公爱〉 經濟部智慧財產局員工消費合作社印製 4 633 9 5 6964twf.doc/008 五、發明說明) 藉由網狀結構之歐姆接觸層以減小光被吸收的損失，進而 提高發光二極體的發光效率。 爲達本發明之上述目的，提出一種發光二極體之結 構，主要包括一基板，基板之一面上具有一布拉格反射鏡 層、一 η型摻雜侷限層、一活性層、一 p型摻雜侷限層、 一電流分散層、一網狀結構之歐姆接觸層、一透光導電氧 化物層與一正面電極，而基板的另一面上則具有一背面電 極。由於歐姆接觸層材質之能隙較小，故會將活性層所發 出的光吸收，因此藉由網狀結構將歐姆接觸層吸收光的面 積減低，以有效避免活性層所發出的光被歐姆接觸層大量 的吸收，進而使發光二極體具有高亮度。 爲讓本發明之上述目的、特徵、和優點能更明顯易 懂，下文特舉一較佳實施例，並配合所附圖式，作詳細說 明如下： 圖式之簡單說明： 第1圓至第3圖分別繪示爲習知中不同發光二極體 之結構示意圖； 第4圖繪示爲不同材料在不同波長時的光吸收係數 分佈圖； 第5圖繪示爲依照本發明一較佳實施例中發光二極 體之結構示意圖； 第6圖繪示爲用以形成網狀結構之歐姆接觸層216 的光罩圖形； 第7圖繪示爲第6圖中光罩的放大示意圖； 6 ---1 I I I I — I — ------I — — 11!^^)^ (請先閱讀背面之注意事項再填窝本頁) 本紙張尺度適用中國國家標準（CNS>A4規格<210 297公釐） 經濟部智慧財產局員工消費合作社印製 633 9 5 A7 6964twf.doc/008 五、發明說明（k ) 第8A圖繪τκ爲固定電流分散層厚度爲6μηι時，對不 同的砷化鎵線寬時所得到相對發光強度對孔徑大小w的關 係圖； 第8Β圖繪示爲固定碑化鎵線寬爲Ιμιη時，針對不同 電流分散層厚度所得到相對發光強度對孔徑大小w的關係 圖；以及 第9圖繪示爲本發明之二極體在每一單位方格內的 電流分佈模擬結果。 圖式之標示說明： 100 : 基板 102、 106 :偈限層 104 : 活性層 108 ： 正面電極 110 ： 背面電極 112 ： 布拉格反射鏡層 114 ： 電流分散層 116 : 透光導電氧化物層 118 ： 歐姆接觸層 200 ： 基板 202 ' 206 :備限層 204 ： 活性層 208 ： 電流分散層 210 ： 正面電極 212 ： 背面電極 7 (請先閱讀背面之注意事項再填寫本頁) in--It 訂·！---- _線. 本紙張尺度適用中國國家標準（CNS)A4規格（210 X 297公釐） 463395 A7 B7 6964twfdoc/008 五、發明說明（L) (請先閱讀背面之注意事項再填寫本頁) 214 :布拉格反射鏡層 216 :歐姆接觸層 218 :透光導電氧化物層 600 :光罩 602 :方形實心部分 604 :斜線部分 較佳實施例 經濟部智慧財產局員ιΗ消費合作社印製 由於習知第1圖中的結構會有電流擁擠的現象存在， 如此亦會造成大部分產生的光被不透光的正面電極108擋 住而反射回半導體本體（Bulk )或被吸光的基板1〇〇所吸 收，造成元件的發光效率大幅降低。而第2圖中加入電流 分散層1H以改善電流擁擠的現象，但是電流分散層114 的厚度必須約爲數十微米才能達到足夠大的電流分散能 力，但賴以成長電流分散層114的有機金屬化學氣相沉積 (MOCVD )其成長速率相當的緩慢，使得元件的製造成本 提高及製造時間增長。故於第3圖中形成透光導電氧化物 層116作爲電流分散層，並在形成透光導電氧化物層116 之前成長P型歐姆接觸層118，以增加透光導電氧化物層 116於半導體上的附著力。但由於歐姆接觸層118的能隙 較活性層104者小，會對二極體發出的光進行再吸收而使 得發光二極體整體亮度大大降低。因此本發明藉由一網狀 結構之歐姆接觸層取代習知的歐姆接觸層118以減小光被 吸收的損失，進而提高發光二極體的發光效率。 首先請參照第5圖，其繪示依照本發明一較佳實施 8 本紙張尺度適用中國國家標準（CNS)A4規格（210 X 297公釐） 463395 6964twf.doc/008 五、發明說明) 例中發光二極體之結構示意圖。首先提供一基板200，基 板200之材質例如爲η型砷化鎵基板。於基板200之一面 上形成一布拉格反射鏡層214，以將射往基板200方向的 光子反射回正面輸出。接著形成侷限層2〇2、活性層204 及侷限層206，其中，侷限層202之材質例如爲η型摻雜 之磷化鋁鎵銦，活性層204之材質例如爲未摻雜之磷化鋁 鎵銦，而侷限層206之材質例如爲ρ型摻雜之磷化鋁鎵銦。 上述之侷限層202與侷限層206係用以夾住活性層204以 增進載子的注入效率。接著在侷限層206上形成電流分散 層 208。 請同時參照第5圖與第6圖，於電流分散層208上 形成一具有網狀結構之歐姆接觸層216’此網狀結構之歐 姆接觸層216的形成方式例如先於電流分散層208上形成 一層歐姆接觸層（未繪示），歐姆接觸層之材質例如爲高 摻雜Ρ型之砷化鎵、磷化鎵或磷砷化鎵等晶格常數相差不 大且窄能隙之材質。接著旋塗上一層光阻（未繪示）。再 以第6圖中之光罩（Mask )600進行曝光的步驟’之後再以 顯影劑將曝光之光阻溶解，最後以此圖案化（Pattern )後之 光阻爲罩幕，將未受光阻覆蓋之歐姆接觸層蝕刻至暴露出 電流分散層208爲止，如此即可形成一具有網狀結構之歐 姆接觸層216。上述第6圖中繪示爲用以形成網狀結構之 歐姆接觸層216的光罩圖形’其中方形實心的部分602表 示欲蝕刻的區域，而斜線部分604則爲經蝕刻後所留下的 網狀歐姆接觸層216位置。 9 (請先閲婧背面之注意事項再填窝本頁) ,裝--------tr---------線 o_ 經濟部智慧財產局員工消費合作社印製 本紙張尺度適用中國國家標準（CNS)A4規格（210 X 297公釐） 經濟部智慧財產局員工消費合作杜印製 463395 6964twf.doc/008 五、發明說明（飞〉 以第6圖中之光罩600形成具有網狀結構之歐姆接 觸層216之後，形成一透光導電氧化物層218覆蓋於電流 分散層208與歐姆接觸層216之上，透光導電氧化物層218 之材質例如爲氧化銦、氧化錫或氧化銦錫等具有良好透光 性之材質。之後，再形成一正面電極210於透光導電氧化 物層上之部分區域，而於基板的另一面上則具有一背面電 極212，其中，正面電極210與背面電極212之材質例如 爲導電性良好之金屬。由於歐姆接觸層216材質之能隙較 小，故會將活性層204所發出的光吸收，因此藉由網狀結 構將歐姆接觸層216吸收光的面積減低，以有效避免活性 層204所發出的光被歐姆接觸層216大量的吸收，進而使 發光二極體具有較高的亮度。 爲確保本發明之元件在經減少歐姆接觸層面積下還 能均与地分佈在整個晶粒，吾人特別將習知一維的電流分 佈關係式推廣成二維’並以電腦模擬電流在9milx9mil的 晶粒大小下之分佈狀態，習知之一維電流階佈關係式如 下： J(x) - 2-Γ , (x/ls+S)2 ,,gtnkT、m 其中，爲金屬下方的電流密度，而J(x)爲距金屬x 處的電流密度，13爲橫向分佈長度（Spreading Length )。 g :電流分散層電導率（Conductivity ) t :電流分散層的厚度 (請先閱讀背面之注意事項再填寫本頁) n n II 訂—t------線 C3. 本紙張尺度適用中國國家標準（CNS)A4規格（210 X 297公釐〉 A7 B7 4 633 9 5 6964twf.doc/008 五、發明說明q ) η:二極體的理想因子 k .波茲曼常數（Boltzmann Constant ) 1·38χ1〇-23 J/K Τ :絕對溫度（0Κ) e :單位電荷値（Elementary Charge ) 1.60218x10'丨9 C 接著請參照第7圖，其繪示爲第6圖中光罩的放大 示意圖。其中’ w爲欲蝕刻矩形的邊長，s爲網狀層（Meshed Layer )的線寬即所形成網狀結構歐姆接觸層之線寬，t爲 電流分散層的厚度，而J(x)爲w、s及t的函數，只要w、 s及ί這三者之一有任何變動，將會影響活性層中任—點 的電流密度大小。以下以磷化鎵爲電流分散層，以砷化鎵 當網狀層模擬本發明結構的電流分散槪況及整體發光強度 並與習知無挖孔洞歐姆接觸層之發光二極體作一比較。 請參照第8Α圖，其繪示爲固定電流分散層厚度爲 6μιη時’對不同的砷化鎵線寬時所得到相對發光強度對孔 徑大小w的關係圖，此處所謂的相對發光強度是對於傳統 非網狀歐姆接觸層者正規化（Normalized )後的値，w = 〇 時的相對強度即表習知無控孔歐姆接觸層者之發光二極體 的發光強度，可由外插至γ軸得到對應的値（=1)，表示 此程式的結果相當合理。對同一種網狀層線寬S而言，此 圖可分兩個部份解釋： (1) 當控空之矩形邊長w小於5μηι時，隨著w愈大， 所形成歐姆接觸層吸光的總區域愈小，發光強度將隨之提 升。 (2) —旦w大到一定程度時（>5〜6μιη)，因電流分佈 本紙張尺度適用中國國家標準（CNS)A4規格（210 X 297公釐） ------------ck--------訂---------線 *〇 (請先閱讀背面之注意事項再填寫本頁) 經濟部智慧財產局員工消費合作社印製 B7 463395 6964twf,d〇c/008 五、發明說明U 〇) 不均甚至分佈區域減小，會使得可發光的區域減小，雖所 形成歐姆接觸層吸光之總面積隨W變大而減小，但整體的 發光強度亦會下降。若固定同一控空之矩形邊長W時，則 當網狀層線寬S愈大，吸光面積愈大，整體亮度必定減弱。 由第8A圖中可得知，當s = l μηι且w = 5 μηι時，所 形成之發光二極體不但具有較均勻的電流分佈特性，亦能 有效地減少歐姆接觸層的吸光面積，故整體的發光強度爲 最大値。 接著請參照第8Β圖，其繪示爲針對不同電流分散層 厚度所得到相對發光強度對孔徑大小w的關係圖。由第8Β 圖中可得知，若孔徑開的不大，則電流分散層厚度t幾乎 對整體的發光強度影響不大。一旦孔徑開得過大 (W>13〜14μιη)時，則電流分散（Current Spreading )的效 果會受限，使得發光區域變小，發光強度亦隨之變小，整 體的發光效率便會大大降低。 由上述的討論可知，本發明所需的電流分散層並不 需第2圖結構中數十μηι的電流分散層，甚至不需使用電 流分散層亦可達到電流分散之目的，且透過網狀歐姆接觸 層亦能改善第3圖中窄能隙吸光的缺點，故此種配合網狀 歐姆接觸層及透光導電氧化物層的架構可大幅提高發光二 極體的亮度。 本發明的模擬係針對注入50mA至發光二極體中所得 到的電流及發光強度比較，希望在均勻的電流分佈下能獲 得比習知採非網狀歐姆接觸層者還大的發光強度。傳統者 12 本紙張尺度適用中國國家標準（CNS)A4規格（210 X 297公釐） (請先閱讀背面之注意事項再填寫本頁) -」裝---- - -訂 ------- 經濟部智慧財產局貝工消費合作社印製A7 B7 4 633 9 5 6964twfdoc / 0〇8 5. Description of the invention (() The present invention relates to the structure of a light-emitting diode, and in particular to a high-brightness light-emitting diode with a mesh ohmic contact layer Structure. At present, the production of light-emitting diodes is gradually mature, so it can be made into large-scale display boards with high reliability. Because the light-emitting diodes used in large-scale display boards must have high-brightness characteristics to make them large The display board is not only large and clear, but also can display its display content at a long distance. Therefore, the development of light-emitting diodes has always moved in the direction of high brightness and low power consumption. The main material of light-emitting diodes is phosphating Aluminum gallium indium (AlGalnP) is a direct energy gap material. Under the condition that the lattice is matched with gallium arsenide (GaAs), the ratio of aluminum and gallium can be adjusted appropriately to change the wavelength of light emission between 550nm and 680nm. The wavelength range is from green to red. Since increasing the aluminum content can increase the energy gap of the material, aluminum gallium indium phosphide with high aluminum content is generally used as the confining layer to clamp the central carrier. The optical layer or active layer is used to improve the carrier injection efficiency, thereby forming a double heterostructure (Double Hetero-structure) light emitting diode with high luminous efficiency. Among them, the energy gap of the confined layer The photon has a large energy, so the confined layer will not absorb the light emitted by the active layer. First, please refer to Fig. 1. Generally, the aluminum gallium phosphide phosphor is a metal organic chemical vapor deposition (Metal Organic Chemical Vapor Deposition (MOCVD) method on the n-type gallium arsenide substrate 100 in order to grow an n-type aluminum gallium indium phosphide confinement layer 102, an aluminum gallium indium phosphide active layer 104, a p-type aluminum gallium indium phosphide Confinement layer 10, and finally a layer of 3 paper is applied. This paper size is applicable to China National Standard (CNS) A4 (210 X 297 mm) < Please read the precautions on the back before filling this page) -rw-- ----- 丨 Order—I—! Line · Printed by the Consumer Cooperatives of the Intellectual Property Bureau of the Ministry of Economic Affairs Printed by the Employee Cooperatives of the Intellectual Property Bureau of the Ministry of Economic Affairs 463395 A7 6964twf.d〇c / 008 37 V. Description of the Invention (V) The front electrode 108 and the back electrode 110 are completed. Fabricating a light emitting diode element. In order to improve the overall luminous intensity of the front side, a Bragg reflector layer 112 (Distributed Bragg Reflector) is usually added under the n-type aluminum gallium indium phosphide confined layer 102, so that the n-type gallium arsenide substrate can be shot. 100 photons are reflected back to the front output. Due to the low mobility of the P-type aluminum gallium indium phosphide material on the epitaxial crystal and the difficulty of high doping, the resistivity will be too high (about 0.5D-cm), so that the lateral current cannot be effectively dispersed. As for the entire crystal grains, since most of the carriers are only implanted directly under the front electrode 108, the active layer 104 at other positions cannot obtain enough carriers for complex light emission. Furthermore, such current crowding (Current Crowding) will also cause most of the generated light to be blocked by the opaque front electrode 108 and reflected back to the semiconductor body (Bulk) or absorbed by the light-absorbing substrate 100, causing the device to emit light. Significantly reduced efficiency. Next, please refer to FIG. 2. In order to solve the above disadvantages, a current-spreading layer 114 is added between the p-type aluminum gallium indium phosphide confinement layer 106 and the front electrode 108 in the structure of FIG. In addition to the excellent transparency of the light emitted from the active layer 104, the current dispersing layer 114 is more important than the aluminum gallium indium phosphide because it can be doped with a higher concentration and has a higher mobility. The dispersion layer 114 has a lower resistivity, which can obtain a more uniform current across the grain. Currently, the materials used in the current dispersion layer 114 are mainly aluminum gallium arsenide (AlGaAs) and gallium phosphide (GaP). However, the current-dispersing layer 114 mentioned above generally needs several tens of micrometers in thickness to achieve a sufficient current-dispersing capacity. However, the growth rate of the organometallic chemical vapor deposition (MOCVD), which depends on the growth of the current-dispersing layer 114, is comparable. Note 4: This paper size is in accordance with Chinese National Standard (CNS) A4 (2K) X 297 mm. (Please read the precautions on the back before filling in this page) t— ϋ ϋ ——Order ------- line -C3 ·-B7 446339 5 6964twfdoc / 008 V. Description of the invention (,) Slow, which makes the component manufacturing cost increase and manufacturing time increase. Next, please refer to FIG. 3 'In order to solve the problem that the growth rate of the current dispersion layer 114 is too slow, a light-transmitting conductive oxide layer 116 is used as the light-emitting diode's current dispersion layer. This conductive oxide not only has good light penetration Permeability, and has a very low resistivity (about 3xl (V4n_cm;), so it can effectively disperse the current across the crystal grains, thereby improving the light-emitting diode's luminous efficiency, generally used as the appropriate for this transparent conductive layer The materials are indium oxide, tin oxide, and indium hafnium oxide. In order to form a good ohmic contact between the light-transmitting conductive oxide and the semiconductor and increase the adhesion of the light-transmitting conductive oxide to the semiconductor, the light-transmitting is usually formed. Before the conductive oxide, a layer of highly doped p-type ohmic contact layer 118 is first grown. The thickness of the ohmic contact layer generally needs to be greater than 500A and the concentration must be greater than 1018cnr3, and the material of the ohmic contact layer 118 is gallium arsenide 'phosphating. Gallium, or gallium phosphorus arsenide (GaAsP) and other materials with small lattice constants and narrow energy gaps. Before the conductive oxide layer is formed as the current dispersion layer 116, p-type European The contact layer ι18 is indeed necessary, but because the energy gap of the ohmic contact layer 118 is smaller than that of the active layer 104, the light emitted by the diode will be reabsorbed and the overall brightness will be greatly reduced. Then refer to FIG. 4, It is shown as the distribution of light absorption coefficients of different materials at different wavelengths. From Figure 4, it can be seen that different compounds such as indium gallium arsenide (GainAsP), gallium arsenide (GaAs), indium phosphide (inp ), Germanium (Ge), gallium phosphide (GaP), silicon (Si) and other materials at an absolute temperature of 300 κ light absorption coefficient α corresponding to the distribution of light wavelength λ "Therefore, the object of the present invention is to propose A light-emitting diode structure, 5! _ — 丨 丨 丨 丨 丨 ^, 1, ill! Order *! · Line (please read the precautions on the back before filling in this page) Employees of the Intellectual Property Bureau of the Ministry of Economic Affairs Copies printed on the paper are in accordance with Chinese National Standard (CNS) A4 specifications ⑽χ 297 Public Love> Printed by the Consumer Cooperatives of the Intellectual Property Bureau of the Ministry of Economic Affairs 4 633 9 5 6964twf.doc / 008 5. Description of the invention) Ohmic contact layer to reduce the loss of light absorption High emission efficiency of light-emitting diodes. In order to achieve the above object of the present invention, a structure of a light emitting diode is proposed, which mainly includes a substrate having a Bragg reflector layer, an n-type doped confinement layer, an active layer, and a p-type dopant on one side of the substrate. The confinement layer, a current dispersion layer, an ohmic contact layer of a mesh structure, a light-transmitting conductive oxide layer, and a front electrode, and the other surface of the substrate has a back electrode. Because the material of the ohmic contact layer has a small energy gap, it will absorb the light emitted by the active layer. Therefore, the area of the ohmic contact layer that absorbs light is reduced by the network structure to effectively prevent the light emitted by the active layer from being contacted by ohms. The layer absorbs a large amount, which in turn makes the light-emitting diode have high brightness. In order to make the above-mentioned objects, features, and advantages of the present invention more comprehensible, a preferred embodiment is described below in detail with the accompanying drawings as follows: Brief description of the drawings: Figure 3 is a schematic diagram of the structure of different light-emitting diodes in the conventional art; Figure 4 is a distribution diagram of the light absorption coefficients of different materials at different wavelengths; Figure 5 is a preferred implementation according to the present invention The schematic diagram of the structure of the light-emitting diode in the example; Fig. 6 shows the mask pattern of the ohmic contact layer 216 for forming a network structure; Fig. 7 shows the enlarged schematic diagram of the mask in Fig. 6; --1 IIII — I — ------ I — — 11! ^^) ^ (Please read the precautions on the back before filling in this page) This paper size applies to Chinese national standards (CNS > A4 specifications < 210 297 mm) Printed by the Consumer Cooperatives of the Intellectual Property Bureau of the Ministry of Economic Affairs 633 9 5 A7 6964twf.doc / 008 V. Description of the invention (k) Figure 8A plots τκ for a fixed current dispersion layer with a thickness of 6 μηι for different arsenic Relationship between the relative luminous intensity and the aperture size w obtained at the gallium line width FIG. 8B shows the relationship between the relative luminous intensity and the aperture size w for different current dispersion layer thicknesses when the line width of the indium gallium is 1 μm; and FIG. 9 shows the diodes of the present invention at each Simulation results of current distribution in one unit square. Description of the drawings: 100: substrates 102, 106: confinement layer 104: active layer 108: front electrode 110: back electrode 112: Bragg reflector layer 114: current dispersion layer 116: light-transmitting conductive oxide layer 118: ohm Contact layer 200: substrate 202 '206: preparation layer 204: active layer 208: current dispersing layer 210: front electrode 212: back electrode 7 (Please read the precautions on the back before filling in this page) in--It Order ·! ---- _Line. This paper size applies to China National Standard (CNS) A4 (210 X 297 mm) 463395 A7 B7 6964twfdoc / 008 V. Description of Invention (L) (Please read the precautions on the back before filling in this (Page 214) 214: Bragg reflector layer 216: Ohmic contact layer 218: Transparent conductive oxide layer 600: Photomask 602: Square solid portion 604: Slanted portion Preferred embodiment Member of the Intellectual Property Bureau of the Ministry of Economy It is known that the structure in Fig. 1 will have a phenomenon of current crowding. This will also cause most of the generated light to be blocked by the opaque front electrode 108 and reflected back to the semiconductor body (Bulk) or the light-absorbing substrate 100. Absorption causes a significant reduction in the luminous efficiency of the element. The current dispersion layer 1H is added in the second figure to improve the current crowding phenomenon. However, the thickness of the current dispersion layer 114 must be about several tens of micrometers in order to achieve a sufficient current dispersion capacity, but the organic metal on which the current dispersion layer 114 is grown depends on Chemical vapor deposition (MOCVD) has a relatively slow growth rate, which increases the manufacturing cost of components and increases the manufacturing time. Therefore, in FIG. 3, a transparent conductive oxide layer 116 is formed as a current dispersion layer, and a P-type ohmic contact layer 118 is grown before the transparent conductive oxide layer 116 is formed to increase the transparent conductive oxide layer 116 on the semiconductor. Of adhesion. However, since the energy gap of the ohmic contact layer 118 is smaller than that of the active layer 104, the light emitted by the diode is reabsorbed, so that the overall brightness of the light emitting diode is greatly reduced. Therefore, the present invention replaces the conventional ohmic contact layer 118 with an ohmic contact layer of a mesh structure to reduce the loss of light absorption, thereby improving the light emitting efficiency of the light emitting diode. First, please refer to FIG. 5, which shows a preferred implementation according to the present invention. 8 The paper size is applicable to the Chinese National Standard (CNS) A4 specification (210 X 297 mm). 463395 6964twf.doc / 008 5. In the example of the invention) Schematic diagram of the light-emitting diode. First, a substrate 200 is provided. The material of the substrate 200 is, for example, an n-type gallium arsenide substrate. A Bragg reflector layer 214 is formed on one surface of the substrate 200 to reflect the photons directed toward the substrate 200 back to the front side for output. Next, a limiting layer 202, an active layer 204, and a limiting layer 206 are formed. The material of the limiting layer 202 is, for example, n-type doped aluminum gallium indium phosphide, and the material of the active layer 204 is, for example, undoped aluminum phosphide. Gallium indium, and the material of the confinement layer 206 is, for example, p-type doped aluminum gallium indium phosphide. The above-mentioned confined layer 202 and confined layer 206 are used to sandwich the active layer 204 to improve the efficiency of carrier injection. A current dispersion layer 208 is then formed on the confinement layer 206. Please refer to FIG. 5 and FIG. 6 at the same time, and form an ohmic contact layer 216 having a network structure on the current dispersing layer 208. The formation method of the ohmic contact layer 216 of the network structure is, for example, formed before the current dispersing layer 208. An ohmic contact layer (not shown). The material of the ohmic contact layer is, for example, a material with a small lattice gap and a narrow energy gap, such as highly doped P-type gallium arsenide, gallium phosphide, or gallium phosphide. Then spin-coat a layer of photoresist (not shown). Then use the mask (Mask) 600 in FIG. 6 to perform the exposure step. Then, the developer is used to dissolve the exposed photoresist. Finally, the photoresist after patterning is used as the mask, and the photoresist will not be blocked. The covered ohmic contact layer is etched until the current dispersion layer 208 is exposed, so that an ohmic contact layer 216 having a network structure can be formed. The above figure 6 shows the mask pattern of the ohmic contact layer 216 used to form the network structure. The square solid portion 602 represents the area to be etched, and the oblique line portion 604 is the net left after etching. The ohmic contact layer 216 is located. 9 (Please read the precautions on the back of Jing before filling in this page), install -------- tr --------- line o_ printed by the Consumer Cooperative of the Intellectual Property Bureau of the Ministry of Economic Affairs Standards are applicable to China National Standard (CNS) A4 specifications (210 X 297 mm). Intellectual Property Bureau, Ministry of Economic Affairs, Consumer Cooperation Du printed 463395 6964twf.doc / 008 5. Description of the invention (flying) with the mask 600 in Figure 6 After forming the ohmic contact layer 216 having a network structure, a light-transmitting conductive oxide layer 218 is formed to cover the current dispersion layer 208 and the ohmic contact layer 216. The material of the light-transmitting conductive oxide layer 218 is, for example, indium oxide, oxide Tin or indium tin oxide has a good light transmissive material. Then, a front electrode 210 is formed on a part of the transparent conductive oxide layer, and a back electrode 212 is formed on the other side of the substrate. Among them, The material of the front electrode 210 and the back electrode 212 is, for example, a metal with good conductivity. Since the material of the ohmic contact layer 216 has a small energy gap, it absorbs light emitted by the active layer 204, so the ohmic contact is made by a mesh structure. Light absorbing area of layer 216 decreases In order to effectively avoid a large amount of light emitted by the active layer 204 from being absorbed by the ohmic contact layer 216, and thereby make the light-emitting diode have a higher brightness. In order to ensure that the elements of the present invention can all be contacted with the area of the ohmic contact layer reduced. The ground is distributed throughout the grain. I specially extended the conventional one-dimensional current distribution relationship to two dimensions, and simulated the distribution of current at a grain size of 9milx9mil by computer. The conventional one-dimensional current distribution relationship is as follows : J (x)-2-Γ, (x / ls + S) 2 ,, gtnkT, m where is the current density below the metal, and J (x) is the current density from the metal x, and 13 is the lateral distribution Length (Spreading Length) g: Conductivity of the current dispersing layer t: Thickness of the current dispersing layer (please read the precautions on the back before filling this page) nn II Order—t ------ line C3. This paper size applies the Chinese National Standard (CNS) A4 specification (210 X 297 mm> A7 B7 4 633 9 5 6964twf.doc / 008 V. Description of the invention q) η: Ideal factor k of the diode k. Bozeman constant (Boltzmann Constant) 1 · 38χ1〇-23 J / K Τ: Absolute temperature (0K) e: Single Elementary Charge 1.60218x10 '丨 9 C Then refer to Figure 7, which is an enlarged schematic diagram of the photomask in Figure 6. where' w is the side length of the rectangle to be etched and s is the mesh layer ( The line width of the Meshed Layer is the line width of the ohmic contact layer of the mesh structure formed, t is the thickness of the current dispersion layer, and J (x) is a function of w, s, and t, as long as the three of w, s, and ί Any change in one of them will affect the current density at any point in the active layer. In the following, gallium phosphide is used as the current dispersing layer, and gallium arsenide is used as the network layer to simulate the current dispersing conditions and overall luminous intensity of the structure of the present invention, and compared with the light emitting diode of the conventional ohmic contact layer without digging holes. Please refer to FIG. 8A, which shows the relationship between the relative luminous intensity and the aperture size w when the thickness of the fixed current dispersion layer is 6 μm for different gallium arsenide line widths. The so-called relative luminous intensity is The normalized 値 of normal non-mesh ohmic contact layer, the relative intensity at w = 0, that is, the luminous intensity of the light emitting diode of the ohmic contact layer without the control hole can be extrapolated to the γ axis The corresponding 値 (= 1) indicates that the result of this program is quite reasonable. For the same line width S of the mesh layer, this figure can be explained in two parts: (1) When the length of the side of the air-controlling rectangle w is less than 5 μm, as the w becomes larger, the formed ohmic contact layer absorbs light. The smaller the total area, the higher the luminous intensity. (2) —when w is too large (> 5 ~ 6μιη), because of the current distribution, the paper size applies the Chinese National Standard (CNS) A4 specification (210 X 297 mm) --------- --- ck -------- Order --------- line * 〇 (Please read the precautions on the back before filling this page) Printed by the Consumer Cooperative of the Intellectual Property Bureau of the Ministry of Economic Affairs B7 463395 6964twf, doc / 008 V. Description of the invention U 〇) The unevenness and even the reduced distribution area will reduce the area that can emit light. Although the total light absorption area of the formed ohmic contact layer decreases as W increases, but The overall luminous intensity will also decrease. If the side length W of the same air control rectangle is fixed, the larger the line width S of the mesh layer, the larger the light absorption area, and the overall brightness must be weakened. It can be seen from Fig. 8A that when s = l μηι and w = 5 μηι, the formed light emitting diode not only has a relatively uniform current distribution characteristic, but also can effectively reduce the light absorption area of the ohmic contact layer. The overall luminous intensity is maximum. Please refer to FIG. 8B, which is a graph showing the relationship between the relative luminous intensity and the aperture size w obtained for different thicknesses of the current dispersion layer. As can be seen from Fig. 8B, if the pore diameter is not large, the thickness t of the current dispersion layer has almost no effect on the overall luminous intensity. Once the aperture is too wide (W > 13 ~ 14μιη), the effect of current spreading will be limited, making the light emitting area smaller, the light intensity will be smaller, and the overall light emitting efficiency will be greatly reduced. From the above discussion, it can be known that the current dispersing layer required by the present invention does not require a current dispersing layer of tens of μηι in the structure of FIG. 2, and the purpose of current dispersing can be achieved without even using a current dispersing layer. The contact layer can also improve the shortcomings of light absorption with a narrow energy gap in the third figure. Therefore, the structure with the mesh ohmic contact layer and the light-transmitting conductive oxide layer can greatly improve the brightness of the light emitting diode. The simulation of the present invention is aimed at comparing the current and luminous intensity obtained by injecting 50 mA into the light emitting diode. It is hoped that under a uniform current distribution, a luminous intensity greater than that of a conventional non-mesh ohmic contact layer can be obtained. The traditional paper size of this paper applies the Chinese National Standard (CNS) A4 specification (210 X 297 mm) (Please read the precautions on the back before filling out this page)-"Packing ------Order ----- -Printed by the Shellfish Consumer Cooperative of the Intellectual Property Bureau of the Ministry of Economic Affairs
A 63395 B7 6964twfdoc/008 五、發明說明（ι\) 電流均勻分佈的大小爲50mA/(9mil)2= 95.679 A/cm2，而 (請先閲讀背面之注意事項再填窝本頁) 本發明之二極體在每一單位方格內（如第7圖所繪示）的 電流分佈模擬結果如第9圖所示，當t = 6μπι、s = Ιμιτι且 w= 5μιη時具最大値爲95.7A/cm2,最小値爲95.659A/cm2。 可見此結構的電流分佈亦非常之均勻，其整體的發光強度 約爲習知者的1.25倍。 綜上所述，本發明至少具有下列優點： 1. 本發明之發光二極體結構中的電流分散層並不需要 數十μπι的厚度，甚至可以不需使用電流分散層亦可達到 電流分散之目的，與習知相較可以節省製程之成本與時 間。 2. 本發明之發光二極體結構中，透過網狀結構之歐姆 接觸層能改善其窄能隙吸收光的缺點，故此種網狀歐姆接 觸層之結構可大幅提高發光二極體的亮度。. 3. 本發明之發光二極體結構，其網狀結構之歐姆接觸 層下之電流分佈非常之均勻，且其整體的發光強度約爲習 知結構的1.25倍。 經濟部智慧財產局員工消費合作社印製 雖然本發明已以一較佳實施例揭露如上，然其並非 用以限定本發明，任何熟習此技藝者，在不脫離本發明之 精神和範圍內，當可作各種之更動與潤飾，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爲準。 本紙張尺度適用中g國家標準（CNS)A4規格（21〇 x 297公釐）A 63395 B7 6964twfdoc / 008 V. Description of the invention (ι \) The current is evenly distributed at 50mA / (9mil) 2 = 95.679 A / cm2, and (please read the precautions on the back before filling this page) The simulation results of the current distribution of the diode in each unit square (as shown in Figure 7) are shown in Figure 9, when t = 6μπι, s = Ιμιτι and w = 5μιη, the maximum value is 95.7A. / cm2, the minimum 値 is 95.659A / cm2. It can be seen that the current distribution of this structure is also very uniform, and its overall luminous intensity is about 1.25 times that of the conventional one. In summary, the present invention has at least the following advantages: 1. The current dispersing layer in the light-emitting diode structure of the present invention does not require a thickness of tens of μm, and the current dispersing layer can be achieved without using a current dispersing layer. Purpose, compared with the knowledge can save the cost and time of the process. 2. In the light-emitting diode structure of the present invention, the ohmic contact layer of the mesh structure can improve the shortcoming of absorbing light with its narrow energy gap. Therefore, the structure of the mesh-shaped ohmic contact layer can greatly improve the brightness of the light-emitting diode. 3. In the light-emitting diode structure of the present invention, the current distribution under the ohmic contact layer of the network structure is very uniform, and its overall luminous intensity is about 1.25 times that of the conventional structure. Printed by the Consumer Cooperatives of the Intellectual Property Bureau of the Ministry of Economic Affairs. Although the present invention has been disclosed as above with a preferred embodiment, it is not intended to limit the present invention. Various modifications and retouching can be made, so the protection scope of the present invention shall be determined by the scope of the attached patent application. This paper size applies to China National Standard (CNS) A4 specification (21 × 297 mm)