201131811 六、發明說明： 【發明所屬之技術領域】 本發明是有關於-種作為照明或顯示器的光源之有色 發光元件，具體上’是有關於一種具有多重活性層之發光 元件。 【先前技術】 因為相較於先前的發光元件，在發光層具有A1GaInP 的發光元件疋較明亮1位數以上，在車載照明或LCD背光 等的與先别的發光二極體不同用途之需要正擴大中。其部 分原因是因為AlGalnP為直接躍遷型’但主要原因是能利 用设置透明且厚的窗層來提高外部量子效率。 此處，AlGalnP系發光元件，是使用AiGaAs或 來作為窗層。但是，AK}aAs層有對於水分會劣化之特性上 的問題，通常在窗層是使用GaP。 但是’為了設置厚GaP窗層，必須在由AlGainp所構 成的發光層上直接接合GaP基板、或是直接結晶成長Gap 的厚膜。直接接合GaP基板之方法，是如日本特開 2006-32837號公報等所表示，會有在與的接合界面產 生障壁層之問題，4 了避免此問題，長時間且高溫的熱處 理是必要的。 又，已知窗層即便設置在發光層的一面，對於提升發 光效率是有效的，進而在另一面亦即在發光層的上下兩面 201131811 设置時，外部量子效率進一步提高。 此時，另一方的窗層也能藉由貼合或結晶成長來形 成’但是在形成發光層時，因為作為基底來使用之GaAs 基板’具有作為光吸收層之功能，在形成窗層前，有必要 將GaAs基板除去。 且說在發光元件，由必要的AlGalnP系材料所構成 之層構造’通常是在GaAs基板上，使用M〇vpE法使其氣 相成長。但是，其膜厚度頂多為1〇ym左右。 雖然AlGalnP系及GaAs系是晶格匹配（iauice matching)系，但是也能利用選擇蝕刻法，因此，利用在 基板與AlGalnP層之間適當地插入需要選擇#刻的層，能 將GaAs基板完全地除去。 i~疋為了製發光所必要的發光層所必要的AlGainp 系材料的總膜厚度，頂多為1〇#m&右’若在只有發光層 的狀態下除去GaAs基板時，殘留晶圓的膜厚度當然為i 〇 左右◊此種10//〇1左右的膜厚度之晶圓，雖然實驗上 月b作處理，但是容易龜裂，而沒有用以通過工業上的製程 所必要的機械強度。 且說，在除去GaAs基板之前，利用使其結晶成長厚 膜GaP層來使晶圓具有機械強度，藉此，Gap層能兼具光 取出層（窗層）與強度保持板，是合理的。 利用結晶成長形成此種厚膜GaP層時，為了具有通過 工業上的製程之充分的機械強度，必要的Gap層之厚度為 2〇μηι以上。但是’為了結晶成長2〇μιη以上的膜厚度之gw 201131811 層，需要數小時〜十幾」 , 成]、時。因為GaP層越厚則侧面光取 出會越增大’所以明知成長時間會變長也無法加以縮短。 又、，相較於通常成長發光層之溫度，⑽層的成長所 兩要的胤度疋需要同等以上的高1 ’發光層部是長時間曝 露在MOVPE成長時的溫度或比其高的溫度。 —且說’通常發光元件所使用的晶圓，在鄰接發光層的 窗層之部& ’設置有用以關人載子之被稱為導電型p型與 n型之P型包覆層與!^型包覆層，而且在p型包覆層與。 :包覆層之間’具有被稱為活性層之層。&，ρ型的窗層 疋鄰接Ρ型包覆層，且η型的窗層是鄰接η型包覆層。 在該Ρ型包覆層中，摻雜有Mg或Ζη等的ρ型不純物， 並利用加熱’依照熱力$，由丨農度高的-方往低的-方擴 散因此，也有可能擴散至活性層中。而且，因為擴散至 活性層中的ρ型不純物容易形成缺陷，在藉由通電等來實 行元件壽命試驗時會形成缺陷，其結果，會造成載子注入 效率低落、光吸收增大等，且造成光輸出功率低落現象。 Ρ型不純物的擴散是非常依存於發光層 (AlGai-dyliM-yP中的A1組成比X ’ X少時，不純物的擴散 快’且不純物不容易滯留。 例如，因為通常活性層的A1組成X較少，相較於 ’’且成X較尚的包覆層’活性層中的不純物擴散速度相對地 較快’不純物不容易滯留。 此處’不純物濃度的絕對量是依照鄰接層的不純物濃 度而變化’鄰接活性層之層為用以關入載子之包覆層是必 201131811 而且’因為相較於活性 所以A1組成X較大，而 要的，又，通常包覆層會被摻雜 層’包覆層為寬能帶隙是必要的 不純物擴散速度比活性層慢。 又’為了不降低對活性a砧 θ 、/主入效率，包覆層必須保 持某種程度以上的濃度之不純 ’物’因此，存在於包覆層中 之不純物會往活性層中擴散。 活性層的厚度具有某 不純物擴散所引起的 種 影 但是，即便有不純物的擴散， 程度以上的厚度時，能作為可抑制 響之構造。 例如’藉由將活性層設f盔 又置為較厚而使其厚度成為會因 為不純物擴散至層中而形成缺陷之程度，即便有不純物擴 散，也能維持在活性層中的發光再結合。但是，該不純物 擴散污染層是非光再結合比其他 他的，舌性層大之層，且是發 光效率低落之主要原因。方# μ 便上’將該型的活性層稱為體 積型（bulk type)活性層^ 此種體積型活性層，就抑制不純物擴散的影響而言是 具有優點，但是因為其只能期待被p型與η型的包覆層所 夾住之載子關入效果’並且被不純物污染的部位具有非發 光再結合層之功能’所以無法提升發光效率。而且此種體 積型活性層只有60%左右的内部量子效率。 作為因應此問題的對策，例如在日本特開则·〇 號公報等之中’揭示_種使用多重量子井_w)構造之方 法’該多重量子井是至少設置2層以上的活性層，且在活 性層與活性層之間設置障壁層。藉由採用此種構造， 201131811 利用提高對量子彳之關入效{，能提高發光效率。 但是，因為MQW的各層的厚度為數奈米〜十幾奈米 (nm)時，是半導體内的電子的德布羅意波長（以Br〇gHe，s wave length)左右，相較於體積活性層，各層的厚度是大幅 度地較薄，不純物擴散對活性層的影響變大。雖然使在 MQW的活性層增加也有解決的可能性，但是必須大幅度地 增加層數，而由於活性層的自吸收，致使内部量子效率低 落。 又，也有一種方法（以下也稱為多重活性層型），其是 對MQW㈣模擬的形式將各層設為德布羅意波長以上的 膜厚度而以少層數來提高發光效率。此時，由於不純物擴 散被適當地㈣，壽命實驗時不容易產生問題，而能製造 長壽命之發光元件。 但是，各層的膜厚度為德布羅意波長以上時，因為在 活性層與活性層之間所設置的障壁層不會產生穿随現象 (穿隨效應)’所以從活性層至鄰接的其他活性層之載子輸 送現象，只有依賴跳_opping)。因為電子的有效質量小， 跳動比較容易，但是電洞的有效 θ 电』幻啕欢質罝比電子大很多，相較 於電子’越過障壁層之跳動的统 切幻統计機率低。因此，特別是 在載子少的低電流區域，會發峰.¥ ^ 口 賞發生在活性層中的載子注入效 率低落及伴隨其所產生的發光效率低落。 又，載子注入效率低落時，奋 β ^成串聯電阻成分的增 大。此效果，在發光二極體這類 ^ 的於低電流區域使用的元 件，s成為重大問題。例如在 I特開平1 1-251687號公 201131811 報中揭不-種藉由插入比活性層寬能帶隙的材料，串聯電 阻成刀增大。但疋’載子變為不容易跳動之情形是與增加 載子關入效果同義，利用截上、χ 我才』用戟子破關入活性層之效果，發光 效率提升。 然而’因為在活性層與活性層之間插人障壁層（波函數 不重疊且能帶隙（bandgap)比活性層大），用以使2〇心的 電流流動所必要的電壓值為25〜3〇v左右，比體積型活 性層時的電壓值1 9V顯著地增大。 若使障壁層的厚度減少為1〇〜2〇nm左右，則串聯電 阻成分停留在活性層的1〜2成左右的的高水準’在㈣ 左右的室溫動作時，該電壓上升（也稱為vf上升）能抑制在 左右’在將2.5〜作電源之機器系統中，不 «成為重大問m，LEDf的發光元件，多半被使用 於屋外，外部壤境為低溫時的特性會成為問題，使用多重 活性層型構造的情況，低溫時的Vf會大幅度地上升。 而且，即便將障壁層的厚度減少至10〜20nm左右， 2電阻成分是停留在體積型活性層# i〜2成左右的高 =準，同時由於減少障壁層的厚度，關入效果變差，發光 輸出功率也低落。若將層厚 廢B U 又/寻化_聯電阻成分高的程 度疋停留於顯示與體積型活性層同樣的特性。 因此，在η型或p型、或是p側與n m以上的厚GaP窗層之AK}aInp 、有 a ^ a 知尤兀件，現狀的技術 疋難以貫現一種具有高内部量子 長壽命之發光… 低串聯電阻成分及 201131811 【發明内容】 [發明所欲解決之問題j 本發明是赛於上述的問題而開發出來，其目的在於提 供-種發光元件’針對伴隨¥ Gap厚膜的成長之發光元 件’可維持先前體積型活性 只土洛}·生層的低電阻之優點，同時能兼 具多重活性層型發光元件所| 士 Μ干所具有的長哥命與高發光效率。 [解決問題之技術手段] 為了解決上述課題，太级ηΒ ω 本發月知:供一種發光元件，是使 用至少具有由（AlxGa, Ιη ρ , hMnhP (〇<χ<1，〇 4<y<〇 6)所構成 的發光層之化合物丰慕>1* I > γ Μ 導體基板而製造出來，該發光層具有 Ρ型包覆層、至少3層以 曰以上的活性層、至少2層以上的障 壁層：η型包覆層，其中該發光元件的特徵在於： 則述障壁層與前述活性層的能帶隙差△ Ε，大於㈣ 且為0.35eV以下。 』如此，將由⑷xGai-x)yIni.yP(〇<x<1〇4<y<〇 6)(以下 載為AlGalnP)所構成之障壁層與活性層的能帶隙差△ E，設為大於OeV且為〇.35eV以下。 藉此相較於將活性層的構造設作體積型活性層的情 況，能將順向電塵^的上升率抑制為3%左右之非常低的 上升率/亦即’是一種長壽命、高發光效率的多重活性層 型構造的發光元件，且能作成與低電阻之體積型活性層大 約相同程度的電阻率之發光元件。 201131811 又’較佳是將前述△ E設為〇·25 以下。 如此’藉由將活性層與障壁層的能帶隙差ΔΕ設為〇25 下，能使順向電壓VfM前的體積型活性層構造的 發光兀件大致相同’而成為一種更低電阻的高發光效率、 長壽命的發光元件。 而且，較佳是將前述ΔΕ設為〇 2eV以上。 如此，藉由將活性層與障壁層的能帶隙差“設為〇.2 eV以上’活性層與障壁層之間的能帶隙保持一定以上，藉 此’能抑制載子的關人功能發生低^。能更容易抑 制順向電壓Vf的上升，同時也能抑制發光效率的低落，且 能更容易成為一種低電阻且高發光效率、長壽命 元 件。 而且’較佳是將前述障壁層的A1組成比χ設為 0<χ<0.9 〇 若障壁層具有如上述的組成時’相較於活性層，能減 慢在障壁層中的不純物的擴散速度，#此，能抑制不純物 滞留在活性層中的情況。因&，能實現載子注人效率的提 升或抑制光吸收。 & 又，前述活性層的厚度，較佳是5nm以上。 如此，利用將活性層的厚度設為能使載子停留 增加之5nm以上，能更提高發光效率。 早 而且，前述障壁層的厚度，較 下 华又佳疋5nm以上5〇nm以 如 此’利用將障壁層的厚。度設為w以上而能抑, 201131811 能更增加載子的關入效 於穿隧效應所產生的載子的透過 果，而能更提南發光效率。 又，利用設A 5〇nm以下，能抑制載子跳動機率的低 落。 [功效] 如以上說明，若依照本發明，針對伴隨著厚膜的 成長之發光元件’能提供一種發光元件，可維持先前體積 型活性層的低電阻之優點1時能兼具多重活性層型發光 元件所具有的長壽命與高發光效率。 【實施方式】 [實施發明的較佳形態] "^ 1工疋不發明不 未被限定於這些例子。帛！圖是顯示本發明的發光元件的 概略的-個例子之圖。又’帛2圖是顯示在本發明的發光 元件所使用的化合物半導體基板的概略的—個例子與發光 層的能帶隙的一個例子之圖。 如第1圖所示，本發明的發光元件10，至少由化合物 半導體基板100與在其表面上所形成的電極丨丨所構成。 而且，如第2圖所示，此化合物半導體基板⑽，至 少由以下所構成：亦即具有作為第一層的η型GW基板 1〇1、作為第三層的P㉟GaP層1〇9、作為第四層的p型 W窗層11〇’且在第—層與第三層之間具有發光層ι〇8 201131811 來作為第二層。 而且，此發光層108是由以下各層所構成：由 (AlxGa丨.x)yIni yP (〇<χ<1，〇 4<y<〇 6)所構成之 n 型包覆層 103、ρ型包覆層1〇7、至少3層以上（在第2圖是層）之 活性層104、及至少2層以上(在第2圖是9層)之障壁層 105 ’其中，障壁層1〇5位於活性層ι〇4與活性層^4之間 且具有比活性層1 04大的能帶隙。 又，此障壁層】05,相較於η型包覆層1〇3和ρ型包 覆層107,其能帶隙相同或較小，且活性| ι〇4與障壁層 105交替地積層一次以上。 而，如第2圖的右側所示，障壁層1〇5的能帶隙 與活性層104的能帶隙Ega之能帶隙差△以,…。，少 於0ev且為0.35eV以下。 又，如第2圖所示，在活性層1〇4與p型包覆層 之間，能設置無掺雜的延遲(set back)層1〇6。又，所謂匈 遲層是指由㈧xGa丨.x)yIn].yP (其中$丨、〇<y<i)所稽 成’且相較於n型包覆層或P型包覆層，Altb X是相同或 較小的層。 一右疋此種構造的發光元件，能改善A1Gainp系高亮度 發光兀件的重要特性亦即壽命(亮度的通電劣化特性)之多 重活性層型’也能將順向電壓Vf維持在與先前技術亦即體 積型相同程度H能作出滿足規格上可容許的水準的 發光元件，並能謀求大幅度地改善。 又，因為疋使用發光壽命長的多重活性層構造之化合 201131811 物半導體基板而製造出來的發光元件，所以能作成長壽命 的發光元件。 卜敗* ▼隙差△ E大於〇.35eV的情況，因為順向電 壓增加，會成為規格上問題之水準，所以△ E是設為〇 下又’么£為〇的情況，因為障壁層與活性成為同一 ’且成亦即成為與先前的體積型活性層完全相同的構造， 無法得到多重活性層的高發光效率、長壽命之優點，所以 △E是設為大於〇。 又’能將△ E設為〇.25eV以下。 藉此將所得到的發光元件的順向電壓’設為與先 刖的體積型活性層構造的發光元件大致相同水準，能得到 更低電阻的高發光效率、長壽命的發光元件· 而且’能將△ E設為〇.2ev以上。 藉此，能將活性層與障壁層之間的能帶隙抑制成較低 為必要以上。亦即’能抑制載子的關人功能之低落。.因 能抑制順向電M Vf的上升，並能抑制發光效率的低 各’而能更容易成為低電阻且高發光效率、長壽命的發 元件。 此處，障壁層的組成比χ能設為9。 、如此，右障壁層的Α1的組成比X在上述範圍内，能成 為串聯電阻更低的障壁層。而且’相較於活性層，能使障 :層的不純物的擴散速度變慢，藉此，因為能抑制不純物 活拴層之滯留’能實現载子注入效率的提升或抑制光 收。 13 201131811 又’活性層的厚度能設為5nm以上。 停二Γ利用將活性層的厚度設為5_以上，能使載子 停留機率增加’能更提高發光效率。 5nm以上、50nm以下。 因為能抑制由於穿隧效應 增加載子的關入效果。藉 而且’障壁層的厚度能設為 若是上述厚度的障壁層時， 所產生的載子的透過，所以能更 此’能更提高發光效率。 又，若是50nm以下時，能抑制載子跳動機率的低落。 另卜關於活性層與障壁層的層數的上限，障壁層與 活性層的能帶隙差Δ P ” ^ ΔΕ滿足大於OeV且為〇.35eV以下的 關係的情況，因為能；告# μ 人& π u马此達成使順向電壓與先前的體積型活性 層相同程度的水準夕Μ里 h +之效果，所以沒有特別限定。 但是’層數太多時，因為製造花費時間致使製造成本 提升，或是因為層數增力。，由於活性層的自吸收致使產生 内部量子效率低落等的問題’所以障壁層數以3〇以下、活 性層數以3 1以下為佳。 而且，以下說明作為此種發光元件的製造方法的一個 例子，但是’當然不被限定於此例子。 首先準備n型GaAs基板來作為成長用單晶基板， 洗淨後放入MOVPE的反應器中。 然後，在先前導入的GaAs基板上，蟲晶成長〇型GaAs 緩衝層。進而’在„型GaAs緩衝層的表面上，藉由M〇vpE 法’蟲晶成長η型包覆層。 隨後，在η型包覆層的表面上，以變更^的組成比父 14 201131811 而成為所需要的構造的方式 日曰成長活性層、障璧層。 利用適當的MOVPE法，遙 此處’是以障壁層盥 〇eV且為〇35ν τ 層的能帶隙差Μ成為大於 以下的方彳 ^ 障壁層# At X，來選擇A1的組成比X。但是， I軍壁層的能帶隙，相較於 疋 ^ π 匕覆層及Ρ型GaP包霜層， 认成相同或較小。 p 土 I復層， 又，使活性層氣相成長至少 相成長至^層以上。而且，是使舌上，並使障壁層氣 積層。進而，障㈣與障壁層= 〜層與障壁層交替地 接打型包覆層與P型包覆層的構^互相不鄰接且沒有鄰 ，能形成延遲層， (其中，0$ 1、 P型包覆層，A1比BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a colored light-emitting element as a light source for illumination or display, and specifically relates to a light-emitting element having multiple active layers. [Prior Art] Since the light-emitting element having the A1GaInP in the light-emitting layer is brighter than one digit compared to the previous light-emitting element, the need for different uses of the light-emitting diodes such as the vehicle illumination or the LCD backlight is positive. Expanded. Part of the reason is that AlGalnP is a direct transition type' but the main reason is to use a transparent and thick window layer to improve external quantum efficiency. Here, the AlGalnP-based light-emitting element uses AiGaAs or a window layer. However, the AK}aAs layer has a problem in that the moisture is deteriorated, and GaP is usually used in the window layer. However, in order to provide a thick GaP window layer, it is necessary to directly bond a GaP substrate on a light-emitting layer composed of AlGainp or to directly crystallize a thick film of Gap. The method of directly bonding the GaP substrate is as shown in Japanese Laid-Open Patent Publication No. 2006-32837, etc., and there is a problem that a barrier layer is formed at the joint interface. 4 This problem is avoided, and long-time and high-temperature heat treatment is necessary. Further, it is known that the window layer is effective for improving the light-emitting efficiency even if it is provided on one surface of the light-emitting layer, and further increases the external quantum efficiency when the other surface is disposed on the upper and lower surfaces of the light-emitting layer 201131811. At this time, the other window layer can also be formed by bonding or crystal growth. However, when the light-emitting layer is formed, since the GaAs substrate used as the substrate functions as a light absorbing layer, before the window layer is formed, It is necessary to remove the GaAs substrate. In the case of a light-emitting element, a layer structure composed of a necessary AlGalnP-based material is usually grown on a GaAs substrate by a M〇vpE method. However, the film thickness is at most about 1 〇 ym. Although the AlGalnP system and the GaAs system are iauice matching systems, a selective etching method can also be utilized. Therefore, the GaAs substrate can be completely formed by appropriately inserting a layer which needs to be selected between the substrate and the AlGalnP layer. Remove. i~疋 The total film thickness of the AlGainp-based material necessary for the light-emitting layer necessary for the light-emitting layer is at most 1〇#m&right'. When the GaAs substrate is removed in the state where only the light-emitting layer is removed, the film of the residual wafer The wafer having a thickness of about 10//1 is of course i. The wafer of the film thickness of about 10//1 is treated, but it is easy to crack, and there is no mechanical strength necessary for the industrial process. Further, it is reasonable to use a GaP layer to have both a light extraction layer (window layer) and a strength maintaining plate by crystallizing the thick film GaP layer before removing the GaAs substrate. When such a thick film GaP layer is formed by crystal growth, the thickness of the Gap layer required is 2 〇μηι or more in order to have sufficient mechanical strength through an industrial process. However, in order to crystallize the thickness of the film thickness of 2〇μηη or more, the layer of gw 201131811 is required to be several hours to ten times. The thicker the GaP layer is, the more the side light is taken out. Therefore, it is known that the growth time is prolonged and cannot be shortened. Further, compared with the temperature of the normally grown light-emitting layer, the growth of the (10) layer requires two or more high levels. The light-emitting layer portion is exposed to a temperature at or higher than the temperature at which the MOVPE grows for a long period of time. . - and said that 'the wafer used for the light-emitting element, the part of the window layer adjacent to the light-emitting layer' is set to be a P-type cladding layer called a conductive p-type and an n-type with a carrier to be used! ^-type cladding, and in the p-type cladding layer. The layer between the cladding layers has a layer called an active layer. &, the p-type window layer 疋 is adjacent to the Ρ-type cladding layer, and the n-type window layer is adjacent to the n-type cladding layer. In the ruthenium-type cladding layer, a p-type impurity such as Mg or Ζn is doped, and the heating is carried out according to the thermal energy, and the diffusion is high to the low-square diffusion. In the layer. Further, since the p-type impurity diffused into the active layer is liable to form defects, defects are formed when the element life test is performed by energization or the like, and as a result, carrier injection efficiency is lowered, light absorption is increased, and the like, and The light output power is low. The diffusion of Ρ-type impurities is very dependent on the luminescent layer (the A1 composition in AlGai-dyliM-yP is less than X 'X, the diffusion of impurities is fast' and the impurities are not easily retained. For example, because the A1 composition of the active layer is usually X Less, the diffusion rate of the impurity in the active layer is relatively faster than that of the ''and the X-preferred coating layer'. The impurity is not easily retained. Here, the absolute amount of the impurity concentration is in accordance with the impurity concentration of the adjacent layer. The change 'the layer adjacent to the active layer is the cover layer for the carrier to be closed is 201131811 and 'because the composition of the A1 is larger than the activity, and the cladding layer is usually doped. 'The cladding layer is a wide band gap. It is necessary that the diffusion rate of impurities is slower than that of the active layer. In order to not reduce the concentration of the active a anvil θ and / the main input efficiency, the coating must maintain a certain level of impureness. Therefore, the impurities present in the coating layer will diffuse into the active layer. The thickness of the active layer has a kind of shadow caused by the diffusion of impurities, but even if there is diffusion of impurities, the thickness is greater than the extent It can be used as a structure that can suppress the sound. For example, 'the thickness of the active layer is set to be thicker, so that the thickness becomes a degree of defects due to diffusion of impurities into the layer, and even if impurities are diffused, it can be maintained. The luminescence in the active layer is recombined. However, the impurity diffusion-contaminated layer is a non-light recombination layer that is larger than the other, the lingual layer, and is the main reason for the low luminous efficiency. The active layer is referred to as a bulk type active layer. Such a volume type active layer is advantageous in terms of suppressing the influence of impurity diffusion, but since it can only be expected to be sandwiched between a p-type and an n-type cladding layer. The carrier loaded with the effect 'and the part contaminated by the impurity has the function of the non-light-emitting recombination layer', so the luminous efficiency cannot be improved. Moreover, the volumetric active layer has an internal quantum efficiency of only about 60%. As a result of this problem, For example, in the Japanese Unexamined Patent Office, etc., the method of 'disclosing a multi-quantum well_w' is used. The multi-quantum well has at least two layers of activity. , And a barrier layer disposed between the active layer and the active layer. By adopting such a configuration, 201131811 can improve the luminous efficiency by improving the efficiency of the quantum enthalpy. However, since the thickness of each layer of the MQW is from several nanometers to ten nanometers (nm), it is the de Broglie wavelength (in Br〇gHe, s wave length) of the electrons in the semiconductor, compared to the volume active layer. The thickness of each layer is greatly thinner, and the influence of diffusion of impurities on the active layer becomes large. Although there is a possibility of solving the increase in the active layer of MQW, the number of layers must be greatly increased, and the internal quantum efficiency is lowered due to self-absorption of the active layer. Further, there is also a method (hereinafter also referred to as a multiple active layer type) in which the thickness of the film is set to be equal to or higher than the De Broglie wavelength in the form of MQW (four) simulation, and the luminous efficiency is improved by a small number of layers. At this time, since the impurity diffusion is appropriately (4), it is not easy to cause a problem in the life test, and a long-life light-emitting element can be manufactured. However, when the film thickness of each layer is above the de Broglie wavelength, since the barrier layer provided between the active layer and the active layer does not cause an occurrence phenomenon (wearing effect), the other activity from the active layer to the adjacent layer The carrier transport phenomenon of the layer is only dependent on hopping _opping). Because the effective mass of electrons is small, the jitter is relatively easy, but the effective θ 』 啕 啕 罝 电 电 电 电 电 电 电 电 电 电 电 电 电 电 电 电 电 电 电 电 电 电 电 电 电 电 电 。 。 。 。 。 。 。 。 。 。 。 。 。 Therefore, especially in a low current region where there is little carrier, a peak is generated. The effect of the carrier injection in the active layer is low and the luminous efficiency accompanying it is low. Further, when the carrier injection efficiency is low, the series resistance component increases. This effect is a major problem in components used in low current regions such as light-emitting diodes. For example, in the case of inserting a material having a wider band gap than the active layer, the series resistance is increased by a knife. However, the situation in which the 载's carrier becomes not easy to jump is synonymous with the effect of increasing the load of the carrier, and the effect of using the scorpion to break into the active layer is utilized, and the luminous efficiency is improved. However, because the barrier layer is inserted between the active layer and the active layer (the wave function does not overlap and the bandgap is larger than the active layer), the voltage value necessary for the current of the 2 〇 heart to flow is 25~ Around 3 〇v, the voltage value of the volume-type active layer is significantly increased by 19 V. When the thickness of the barrier layer is reduced to about 1 〇 to 2 〇 nm, the series resistance component stays at a high level of about 1 to 2% of the active layer, and the voltage rises when it is operated at room temperature of about (4). It is possible to suppress the characteristics of the LEDs in the machine system that is 2.5 to the power supply, and the LEDs are mostly used outside the house, and the characteristics of the external soil at low temperatures become a problem. In the case of using a multiple active layer type structure, Vf at a low temperature is greatly increased. Further, even if the thickness of the barrier layer is reduced to about 10 to 20 nm, the two-resistance component stays high in the volume-active layer #i~2, and the effect of the barrier is deteriorated by reducing the thickness of the barrier layer. The luminous output power is also low. If the layer thickness of the waste B U / / _ _ _ resistance component is high, the 疋 stays on the same characteristics as the volume type active layer. Therefore, in the η-type or p-type, or the AK}aInp of the thick GaP window layer of the p side and the nm or more, there is a ^ a knowing, and the current state of the art is difficult to achieve a high internal quantum long life. LIGHTING... Low series resistance component and 201131811 [Description of the Invention] [Problem to be Solved by the Invention] The present invention has been developed in view of the above problems, and an object thereof is to provide a light-emitting element for growth of a thick film accompanying a Gap The light-emitting element 'maintains the advantages of the low-resistance of the previous volume-type active only turtle}, and at the same time, it can combine the long-lived and high luminous efficiency of the multiple active-layer light-emitting elements. [Technical means for solving the problem] In order to solve the above problem, the gradation η Β ω is known as a light-emitting element, and is used at least by (AlxGa, Ιη ρ , hMnhP (〇<χ<1, 〇4<y< 〇6) The compound of the light-emitting layer is composed of a γ Μ conductor substrate, and the light-emitting layer has a ruthenium-type cladding layer, at least 3 layers of active layers above 曰, at least 2 a barrier layer above the layer: an n-type cladding layer, wherein the light-emitting element is characterized in that: the energy gap difference Δ Ε between the barrier layer and the active layer is greater than (4) and is less than 0.35 eV. 』 Thus, by (4) xGai- x) yIni.yP (〇<x<1〇4<y<〇6) (Downloaded as AlGalnP) The band gap difference ΔE between the barrier layer and the active layer is set to be larger than OeV and is 〇. Below 35eV. Therefore, compared with the case where the structure of the active layer is set as the volume type active layer, the rate of increase of the forward electric dust can be suppressed to a very low rate of increase of about 3% / that is, a long life and a high A light-emitting element of a multiple active layer structure having luminous efficiency, and a light-emitting element having a resistivity of approximately the same degree as a low-resistance bulk active layer. 201131811 Further, it is preferable to set the aforementioned Δ E to 〇·25 or less. Thus, by setting the energy band gap ΔΕ of the active layer and the barrier layer to 〇25, the light-emitting element of the volume-type active layer structure before the forward voltage VfM can be made substantially the same, and becomes a lower resistance. A light-emitting element with luminous efficiency and long life. Further, it is preferable to set the aforementioned ΔΕ to 〇 2 eV or more. In this way, by setting the energy band gap difference between the active layer and the barrier layer to “above 〇.2 eV or more”, the energy band gap between the active layer and the barrier layer is kept constant, thereby suppressing the function of the carrier. The occurrence of low ^ can more easily suppress the rise of the forward voltage Vf, and at the same time, can suppress the decrease of the luminous efficiency, and can be more easily become a low-resistance and high luminous efficiency, long-life element. Moreover, it is preferable to form the barrier layer. The composition ratio of A1 is set to 0 < χ < 0.9 〇 If the barrier layer has the composition as described above, the diffusion rate of the impurities in the barrier layer can be slowed down compared to the active layer, thereby preventing the retention of impurities in the barrier layer. In the case of the active layer, the efficiency of the carrier injection can be improved or the light absorption can be suppressed. Further, the thickness of the active layer is preferably 5 nm or more. Thus, the thickness of the active layer is set to It is possible to increase the luminous efficiency by increasing the carrier retention by more than 5 nm. Early, the thickness of the barrier layer is more than 5 nm to 5 〇 nm, so that the thickness of the barrier layer is set to w. The above can be suppressed, 20 1131811 can increase the carrier's effect on the transmission effect of the carrier generated by the tunneling effect, and can improve the south luminous efficiency. Moreover, by setting A 5 〇 nm or less, the carrier jump rate can be suppressed. [Efficacy] As described above, according to the present invention, a light-emitting element which is accompanied by the growth of a thick film can provide a light-emitting element which can maintain the advantage of low resistance of the prior volume-type active layer, and can have multiple active layer types. The long life and high luminous efficiency of the light-emitting element. [Embodiment] [Better Mode for Carrying Out the Invention] The invention is not limited to these examples. The figure is a light-emitting element of the present invention. A diagram of an example of a schematic diagram of a compound semiconductor substrate used in the light-emitting element of the present invention and an example of an energy band gap of the light-emitting layer. As shown in the figure, the light-emitting element 10 of the present invention is composed of at least a compound semiconductor substrate 100 and an electrode layer formed on the surface thereof. Further, as shown in Fig. 2, the compound semiconductor substrate (10) At least, it is composed of an n-type GW substrate 1〇1 as a first layer, a P35GaP layer 1〇9 as a third layer, and a p-type W-window layer 11〇' as a fourth layer. - There is a light-emitting layer ι〇8 201131811 between the layer and the third layer as the second layer. Moreover, the light-emitting layer 108 is composed of the following layers: (AlxGa丨.x)yIni yP (〇<χ<1 , 〇4<y<〇6), n-type cladding layer 103, p-type cladding layer 1〇7, at least 3 layers or more (in FIG. 2 is an active layer 104), and at least 2 layers or more The barrier layer 105' (in FIG. 2 is a 9-layer layer), wherein the barrier layer 1〇5 is located between the active layer ι 4 and the active layer 4 and has a larger band gap than the active layer 104. Moreover, the barrier layer] 05 has the same or smaller band gap than the n-type cladding layer 1〇3 and the p-type cladding layer 107, and the active layer 与4 and the barrier layer 105 are alternately laminated once. the above. Further, as shown on the right side of Fig. 2, the band gap of the energy band gap of the barrier layer 1 〇 5 and the band gap Ega of the active layer 104 is Δ. , less than 0 ev and less than 0.35 eV. Further, as shown in Fig. 2, an undoped set back layer 1〇6 can be provided between the active layer 1〇4 and the p-type cladding layer. Further, the so-called Hunger layer means that (8) xGa丨.x)yIn].yP (where $丨, 〇<y<i) is formed and compared to an n-type cladding layer or a p-type cladding layer, Altb X is the same or smaller layer. A light-emitting element of such a structure can improve the important characteristics of the A1Gainp-based high-brightness light-emitting element, that is, the multiple active layer type of lifetime (lighting deterioration characteristic of brightness) can also maintain the forward voltage Vf in the prior art. In other words, the volume type is the same as H, and a light-emitting element that satisfies the allowable level of the specification can be obtained, and can be greatly improved. Further, since the light-emitting element manufactured by the compound semiconductor substrate of the 201131811 is used as the multiple active layer structure having a long light-emitting lifetime, it is possible to use a light-emitting element having a long life. Bu = * ▼ gap difference △ E is greater than 〇.35eV, because the forward voltage increases, it will become the standard of the problem, so △ E is set to the underarm and then the case is because of the barrier layer and The activity is the same and the structure is completely the same as that of the previous volume-type active layer, and the advantages of high luminous efficiency and long life of the multiple active layers are not obtained, so ΔE is set to be larger than 〇. Further, Δ E can be set to 〇.25 eV or less. Thereby, the forward voltage ' of the obtained light-emitting element is set to be substantially the same level as that of the light-emitting element of the volume-type active layer structure of the prior art, and a light-emitting element having a lower resistance and a high luminous efficiency and a long life can be obtained. Let Δ E be 〇.2 ev or more. Thereby, the energy band gap between the active layer and the barrier layer can be suppressed to be lower than necessary. That is to say, it can suppress the lowing of the function of the carrier. Since it is possible to suppress the rise of the forward electric power M Vf and to suppress the low luminous efficiency, it is possible to easily become a low-resistance, high luminous efficiency, and long-life emitting element. Here, the composition ratio χ of the barrier layer can be set to 9. Thus, the composition ratio X of the crucible 1 of the right barrier layer is within the above range, and it can be a barrier layer having a lower series resistance. Further, the diffusion rate of the impurity of the layer can be made slower than that of the active layer, whereby the retention of the active layer of the impurity can be suppressed, and the efficiency of the carrier injection can be improved or the light can be suppressed. 13 201131811 Further, the thickness of the active layer can be set to 5 nm or more. By using the thickness of the active layer to be 5 or more, it is possible to increase the probability of the carrier staying, and the luminous efficiency can be further improved. 5 nm or more and 50 nm or less. This is because it suppresses the effect of increasing the load of the carrier due to tunneling. Further, when the thickness of the barrier layer can be set to be the barrier layer of the above thickness, the generated carrier can be transmitted, so that the luminous efficiency can be further improved. Moreover, when it is 50 nm or less, the fall of the carrier jumper rate can be suppressed. In addition, regarding the upper limit of the number of layers of the active layer and the barrier layer, the energy band gap difference Δ P ′ ′ Δ 障 of the barrier layer and the active layer satisfies a relationship greater than OeV and is not more than 3535EV, because it can; & π u horse achieves the effect that the forward voltage is the same as that of the previous volume-type active layer, so it is not particularly limited. However, when the number of layers is too large, manufacturing costs are incurred because of manufacturing time. The increase in the number of layers is caused by the self-absorption of the active layer, which causes problems such as a decrease in internal quantum efficiency. Therefore, the number of barrier layers is 3 Å or less, and the number of active layers is preferably 3 1 or less. An example of the method for producing such a light-emitting device is not limited to this example. First, an n-type GaAs substrate is prepared as a single crystal substrate for growth, washed, and placed in a reactor of MOVPE. On the previously introduced GaAs substrate, the insect crystal grows into a GaAs-type GaAs buffer layer. Further, on the surface of the GaAs buffer layer, the n-type cladding layer is grown by the M〇vpE method. Subsequently, on the surface of the n-type cladding layer, the active layer and the barrier layer are grown in a manner that changes the composition of the composition to be a desired structure than the parent 14 201131811. By using the appropriate MOVPE method, the composition ratio X of A1 is selected by the barrier band 盥 V eV and the band gap difference 〇 of the 〇35ν τ layer becomes greater than the following barrier layer # At X. However, the energy band gap of the I Army wall layer is considered to be the same or smaller than the 疋 ^ π 匕 coating and the Ρ-type GaP frost layer. p The soil I layer, and the active layer vapor phase growth at least gradually grows to above the layer. Moreover, it is to make the tongue and make the barrier layer a gas layer. Further, the barrier layer (4) and the barrier layer = the layer and the barrier layer are alternately connected to each other and the structure of the P-type cladding layer is not adjacent to each other and has no adjacent layer, and a retardation layer can be formed, (where 0$1, P Type cladding, A1 ratio
進而，在最表面側的活性層形成後 此延遲層是由無㈣的（AlxGaNx)yIni yP 〇<y<i)所構成，且相較於n型包覆層或 χ是相同或較小。 然後’在最表面側的活性厝Further, after the formation of the active layer on the outermost surface side, the retardation layer is composed of (4) (AlxGaNx) yIni yP 〇 < y < i), and is the same or smaller than the n-type cladding layer or ruthenium . Then 'on the most surface side of the active 厝
、 ⑴J石Γ玍層之表面上，藉由MOVPE 法'’遙晶成長ρ型包覆層、刑 ρ主匕復赝Ρ型GaP層，來得到Μ〇磊晶 基板。 隨後幵V成ρ型GaP窗層。此窗層的形成，|將先前 所得到的MO蟲晶基板從M〇vpE的反應器取出，並放入 E法的反應器内。隨後’擦雜Zn來蟲晶成長p型Gap 窗層。 隨後，除去GaAs基板及GaAs緩衝層。藉此，使η型 包覆層露出。 然後，在除去GaAs基板等而露出的η型包覆層的表 15 201131811 面，貼上η型GaP基板、或是使用HvpE法並藉由磊晶成 長來形成η型GaP層，能得到化合物半導體基板。 在藉由上述M0VPE法或HVPE法來進行氣相成長 時，可使用通常的條件。 然後，切斷所得到的化合物半導體基板，並加工成為 晶粒且進行電極附加等，能得到發光元件。 [實施例] 以下，顯不貫施例及比較例來更具體地說明本發明， 但是本發明並沒有被限定於這些例子。 (實施例1) 製ϋ如第2圖所不的化合物半導體基板，並製造如第 1圖所示的發光元件。 八體上，疋在厚度為28(Vm的ϋ型GaAs基板（15。斜 角（off angle))的主表面上，藉由M〇vpE法蠢晶成長厚度 〇.5μΓΠ的11型GaAs緩衝層、厚度2.3μιη的n型AlGalnP 層(nil覆層）、9對厚度〇.〇3μπι的無摻雜AinGaijnp 層（活性層）與厚度〇.〇3师的無推雜‘GW層（障壁 層）+厚度〇.〇3_的無#雜从如xjnp層（活性層）、厚度 〇·7μΠ1的無摻雜A1GaInP層（延遲層）、厚度1·6μιη的p型 偷叫型包覆層）、厚度以“的ρ型GaP層（窗層）， 隨後藉由HVPE法’蠢晶成長9()//仿的p型㈣層（窗層 …另外，活性層的A1組成比Xa與障壁磨的A1組成比〜， …表1所不的組成比’且將活性層與障壁層的能帶 16 201131811 隙差△ E設為〇.24eV。 隨後，除去η型GaAs基板與n型QaAs緩衝層，並貼 上η型GaP基板。 然後，進行電極形成、切割及電極附加，來製造發光 元件》 為了評價所製造的發光元件之特性，進行如以下所示 的評價。 首先，為了評價發光效率，利用積分球來測定流動直 流電流20mA時的全方位光輸出功率。而且，作為壽命特 性的評價’是利用設成直流電流50mA、環境溫度85。(：的 加速試驗，來評價1 00小時後的發光效率，並評價相對於 初期輸出功率之劣化程度。 而且’進行在環境溫度25t中用以流動2〇mA的電流 所必要的電壓（順向電壓vf)的評價。而且，進行溫度為85 c、濕度為50%、順向電流為50mA、通電時間為1〇〇小時 之加速試驗，來評價順向電壓Vf的變化率（Vf life)。進而， 進行在低溫（-40°C )中用以流動20mA的電流所必要的順向 電壓Vf(LT Vf)的評價。 將這些結果的一部分表示於表1中。 (比較例1) 製造如第5圖所示的化合物半導體基板2〇〇,並製造 由該化合物半導體基板所製造的發光元件。 具體上，是在厚度為280 μπι的η型Ga As基板（15。斜 17 201131811 角（off angle))的主表面上，藉由m〇vpe法，遙晶成長厚度 0.5μπι的η型GaAs緩衝層、厚度2 的n型 層（η型包覆層）203、厚度〇 6μηι的無摻雜A^Gunp層 (活性層）204、厚度〇.7μηι的無摻雜AiGaInp層（延遲 層）206、厚度的p型A1GaInp(p型包覆層㈣卜厚 度2.5μΠ1的P型GaP層（窗層）2〇9，隨後，藉由HvpE法， 磊晶成長90μιη的p型GaP層（窗層）21〇。 另外，活性層的A1組成比〜為〇.〇9。此時，未存在 障壁層’能帶隙差△ E為〇。(1) On the surface of the J sarcophagus layer, the Μ〇-type epitaxial GaP layer is obtained by the MOVPE method ''the crystal growth ρ-type cladding layer and the ρ main 匕 匕 type Ga 赝Ρ type GaP layer. Then 幵V becomes a p-type GaP window layer. The formation of this window layer, the previously obtained MO insect crystal substrate was taken out from the reactor of M〇vpE, and placed in the reactor of the E method. Subsequently, Zn was added to the worm to grow the p-type Gap window layer. Subsequently, the GaAs substrate and the GaAs buffer layer are removed. Thereby, the n-type cladding layer is exposed. Then, the n-type GaP substrate is attached to the surface of the n-type cladding layer exposed by removing the GaAs substrate or the like, or the n-type GaP layer is formed by epitaxial growth using the HvpE method, whereby the compound semiconductor can be obtained. Substrate. When the vapor phase growth is carried out by the above M0VPE method or HVPE method, usual conditions can be used. Then, the obtained compound semiconductor substrate is cut, processed into crystal grains, and an electrode is added or the like to obtain a light-emitting element. [Examples] Hereinafter, the present invention will be more specifically described by way of examples and comparative examples, but the present invention is not limited to these examples. (Example 1) A compound semiconductor substrate as shown in Fig. 2 was produced, and a light-emitting element as shown in Fig. 1 was produced. On the octahedron, on the main surface of a ϋ-type GaAs substrate (15. off angle) with a thickness of 28 (Vm), an 11-type GaAs buffer layer having a thickness of 55 μΓΠ is grown by M〇vpE method. , n-type AlGalnP layer (nil cladding) with thickness of 2.3μιη, undoped AinGaijnp layer (active layer) with thickness of 9 pairs of 〇.〇3μπι and thickness of GW layer (damper layer) of thickness 〇.3 + thickness 〇.〇3_ of the ### from the xjnp layer (active layer), the thickness of 〇7μΠ1 of the undoped A1GaInP layer (retardation layer), the thickness of 1·6μιη p-type sneak-type cladding layer), The thickness is "p-type GaP layer (window layer), followed by HVPE method" stupid crystal growth 9 () / / imitation p-type (four) layer (window layer ... In addition, the active layer A1 composition ratio Xa and barrier grinding A1 composition ratio ~, ... the composition ratio of Table 1 'and the gap between the active layer and the barrier layer energy band 16 201131811 Δ E is set to 〇.24eV. Subsequently, the n-type GaAs substrate and the n-type QaAs buffer layer are removed, And attaching an n-type GaP substrate. Then, electrode formation, dicing, and electrode addition are performed to manufacture a light-emitting element. In order to evaluate the characteristics of the manufactured light-emitting element, First, in order to evaluate the luminous efficiency, the omnidirectional optical output power at a flow direct current of 20 mA was measured by an integrating sphere. Further, the evaluation of the life characteristics was performed by using a direct current of 50 mA and an ambient temperature of 85. (In the accelerated test, the luminous efficiency after 100 hours was evaluated, and the degree of deterioration with respect to the initial output power was evaluated. Further, 'the voltage necessary to flow a current of 2 mA at an ambient temperature of 25 Torr (forward) Evaluation of voltage vf) Further, an acceleration test in which the temperature was 85 c, the humidity was 50%, the forward current was 50 mA, and the energization time was 1 hr was performed to evaluate the rate of change of the forward voltage Vf (Vf life). Further, evaluation of the forward voltage Vf (LT Vf) necessary for flowing a current of 20 mA at a low temperature (-40 ° C) was performed. A part of these results are shown in Table 1. (Comparative Example 1) Manufacturing as The compound semiconductor substrate shown in Fig. 5 is produced by manufacturing a light-emitting element made of the compound semiconductor substrate. Specifically, it is an n-type Ga As substrate having a thickness of 280 μm (15. Oblique 17 2011) On the main surface of the 31811 off angle, an n-type GaAs buffer layer having a thickness of 0.5 μm, an n-type layer having a thickness of 2 (n-type cladding layer) 203, and a thickness of 〇6 μηι are grown by a m〇vpe method. Undoped A^Gunp layer (active layer) 204, undoped AiGaInp layer (retardation layer) 206 of thickness 〇7μηι, p-type A1GaInp of thickness (p-type cladding layer (4) P-type GaP of thickness 2.5μΠ1 The layer (window layer) 2〇9, followed by epitaxial growth of a 90 μm p-type GaP layer (window layer) 21 藉 by the HvpE method. Further, the composition ratio of the A1 of the active layer is 〇.〇9. At this time, there is no barrier layer' energy band gap difference Δ E is 〇.
Ik後，除去n型GaAs基板與n型GaAs緩衝層，並貼 上η型GaP基板201。 然後，進行電極形成、切割及電極附加，來製造發光 元件。 隨後，進行與實施例i同樣的評價。其結果也如表（ 所示。 H死例2) 針對實施例1，除了將活性層的Μ組成比、設為 〇·3〇 ’將障壁層的A1組成比Xb設為〇 85，且將△ ε設為 〇.3糾以外’ #由與實施例1同樣的方法來製造化合二 導體基板及發光元件。並且，進行與實施例1同樣的評價， 其結果是如表1所示。 (比較例2) 201131811 製造如第6圖所示的化合物半導體基板300，並製造 發光元件。 具體上’是在厚度為2 80μηι的η型GaAs基板（15。斜 角（off angle))的主表面上，藉由M〇vpE法，磊晶成長厚度After Ik, the n-type GaAs substrate and the n-type GaAs buffer layer are removed, and the n-type GaP substrate 201 is attached. Then, electrode formation, dicing, and electrode addition were performed to fabricate a light-emitting element. Subsequently, the same evaluation as in Example i was carried out. The results are also shown in the table (H-dead example 2). In the example 1, except that the Μ composition ratio of the active layer is set to 〇·3〇', the A1 composition ratio Xb of the barrier layer is set to 〇85, and Δ ε was set to 〇.3 Correction. # A composite two-conductor substrate and a light-emitting element were produced in the same manner as in Example 1. Further, the same evaluation as in Example 1 was carried out, and the results are shown in Table 1. (Comparative Example 2) 201131811 A compound semiconductor substrate 300 as shown in Fig. 6 was produced, and a light-emitting element was produced. Specifically, it is an epitaxial growth thickness by the M〇vpE method on the main surface of an n-type GaAs substrate (15. off angle) having a thickness of 280 μm.
〇·5μπι的η型GaAs緩衝層、厚度2 3μηι的^型AlGalnP 層（η型包覆層）303、9對厚度0.03μηι的無摻雜AlxaGa|_xaInp 層（活性層）304及厚度0.03μιη的無摻雜AixbGai xbInp層（障 壁層)305 +厚度〇.〇3pm的無摻雜AlxaGai xJnp層（活性 層）3 04厚度〇.7μηι的無摻雜AlGalnP層（延遲層）3〇6、厚 度1·6μΐη的p型A1GaInP(p型包覆層）3〇7、厚度2.5#爪的 P型GaP層（窗層）309,隨後藉由Ηνρ^^，磊晶成長9〇# m的Ρ型GaP層（窗層）310。 另外，活性層的A1組成比Xa為〇 〇9，障壁層的A1組 成比xb為0.85’此時的為〇 46eV。 隨後’除去η型GaAs基板與n型GaAs緩衝層，並貼 上η型GaP基板301。 然後，進行電極形成、切割及電極附加，來製造發光 元件。隨後，進行與實施们同樣的評價。其結果是如表 1所示。η·5μπι n-type GaAs buffer layer, thickness 2 3μηι-type AlGalnP layer (n-type cladding layer) 303, 9 pairs of thickness 0.03μηι undoped AlxaGa|_xaInp layer (active layer) 304 and thickness 0.03μιη Undoped AixbGai xbInp layer (barrier layer) 305 + thickness 〇.〇3pm undoped AlxaGai xJnp layer (active layer) 3 04 thickness 〇.7μηι undoped AlGalnP layer (retardation layer) 3〇6, thickness 1 · 6 μΐη p-type A1GaInP (p-type cladding layer) 3〇7, thickness 2.5# claw P-type GaP layer (window layer) 309, followed by Ηνρ^^, epitaxial growth of 9〇# m Ρ-type GaP Layer (window layer) 310. Further, the A1 composition ratio Xa of the active layer was 〇 〇 9 , and the A1 composition ratio of the barrier layer was 0.85' at this time, which was 〇 46 eV. Subsequently, the n-type GaAs substrate and the n-type GaAs buffer layer are removed, and the n-type GaP substrate 301 is attached. Then, electrode formation, dicing, and electrode addition were performed to fabricate a light-emitting element. Subsequently, the same evaluation as the implementers was carried out. The result is shown in Table 1.
19 201131811 相較於比較例1之具有體積型活性層的發光元件多 重活性層型的發光元件亦即實施例卜2或比較例2的發光 元件之發光效率，當將比較例1設為^時，為105(實施例 1)、1.12(實施例2)、丨.^比較例2)。又，發光壽命，當將 比較例！設為！時，為i刺（實施例…i 14(實施例2)、 1.HK比較例2)，得知若越增大能帶隙的差則越能改善發光 效率、發光壽命。又，關於1GM、時通電後的vf(vfHfe)， 任一種都幾乎沒有差異而無問題。 但是’如表1或第3圖所示，順向電壓是隨著λε的 上升而同時上升，ΔΕ大於〇.35Εν的情況，是達到實用上 會產生問題之水準。又，也得知^在〇 2〜〇 25eV之間 時’順向電壓的上升率較小。 又，關於在低溫（-40°C )的環境下之順向電壓，是如表 1或第4圖所示，也是△E越增加則在低溫的順向電壓也上 升，且△ E大於0.35eV的情況，順向電壓是大幅度地上升。 又’也得知△ E在0.2〜〇.25eV之間時，同樣地，在低溫的 順向電壓的上升率也能較小。 因此，若增大能帶隙差ΔΕ，雖然能改善發光效率或發 光壽命，但是Vf的上升率也變大。因此，得知有必要將^ E控制在Vf不會變為太高而能改善發光效率的範圍内，也 就是大於OeV而在〇.35eV以下，更佳是在〇2eV以上 0.35eV以下的範圍内。 另外，本發明並未被限定於上述實施形態。上述實施 形態是例示性，凡是具有與本發明的申請專利範圍所記載 20 201131811 的技術思想實質上相同構成，可達成相同作用效果的實施 形態’無論如何都包含在本發明的技術範圍内。 【圖式簡單說明】 • 第1圖是顯示本發明的發光元件的概略的—個例子之 圖。 第2圖是顯示在本發明的發光元件所使用的化合物半 導體基板的概略與發光層的能帶隙的概略的一個例子之 圖。 第3圖是顯示本發明的實施例及比較例的發光元件的 障壁層與活性層的能帶隙差△ E與順向電壓Vf的關係之圖 表。 第4圖是顯示實施例及比較例的發光元件的能帶隙差 △ E與在低溫（-40°C )中的順向電壓Vf的關係之圖表。 第5圖是顯示在比較例丨的發光元件所使用的化合物 半導體基板的概略之圖。 第6圖是顯示在比較例2的發光元件所使用的化合物 半導體基板的概略之圖。 21 201131811 【主要元件符號說明】 10 發光元件 11 電極 100、200、300 化合物半導體基板 101、201、301 η型GaP基板 103 ' 203'303 η型包覆層 104、204、304 活十级 105、305 障壁層 106、206、306 延遲層 107、207、307 ρ型包覆層 108 發光^ 109、209、309 ρ型GaP層 110、210、310 ρ型GaP窗層 2219 201131811 Light-emitting element having a volume-type active layer of Comparative Example 1 The light-emitting element of the multiple active layer type, that is, the light-emitting element of Example 2 or Comparative Example 2, when Comparative Example 1 is set to ^ The ratio is 105 (Example 1), 1.12 (Example 2), and Comparative Example 2). Also, the luminescence lifetime, when the comparison example! Set to! In the case of the i thorn (Examples i14 (Example 2) and 1.HK Comparative Example 2), it was found that the higher the band gap, the better the luminescence efficiency and the luminescence lifetime. In addition, there is almost no difference between the 1 GM and the vf (vfHfe) after the power is turned on, and there is no problem. However, as shown in Table 1 or Fig. 3, the forward voltage rises simultaneously with the rise of λε, and ΔΕ is larger than 〇.35Εν, which is a practical level of problem. Further, it is also known that the rate of increase in the forward voltage is small when 〇 2 to 〇 25 eV. In addition, the forward voltage in a low temperature (-40 ° C) environment is as shown in Table 1 or Figure 4, and the ΔE increases as the ΔE increases, and the forward voltage also rises at a low temperature, and Δ E is greater than 0.35. In the case of eV, the forward voltage is greatly increased. Further, when ΔE is between 0.2 and e25 volts, the rate of increase in the forward voltage at a low temperature can be made small. Therefore, if the band gap difference ΔΕ is increased, although the luminous efficiency or the luminous lifetime can be improved, the rate of increase of Vf also becomes large. Therefore, it has been found that it is necessary to control ^ E within a range in which Vf does not become too high to improve luminous efficiency, that is, greater than OeV and less than 35.35 eV, and more preferably in the range of 〇2 eV or more and 0.35 eV or less. Inside. Further, the present invention is not limited to the above embodiment. The above-described embodiment is exemplified, and the embodiment having substantially the same configuration as the technical idea described in the scope of the patent application of the present invention is disclosed in the technical scope of the present invention. BRIEF DESCRIPTION OF THE DRAWINGS Fig. 1 is a view showing an outline of an example of a light-emitting element of the present invention. Fig. 2 is a view showing an outline of an outline of a compound semiconductor substrate used in the light-emitting element of the present invention and an outline of an energy band gap of the light-emitting layer. Fig. 3 is a graph showing the relationship between the band gap difference ΔE of the barrier layer and the active layer of the light-emitting element of the embodiment and the comparative example of the present invention and the forward voltage Vf. Fig. 4 is a graph showing the relationship between the band gap difference ΔE of the light-emitting elements of the examples and the comparative examples and the forward voltage Vf at a low temperature (-40 °C). Fig. 5 is a schematic view showing a compound semiconductor substrate used in a light-emitting element of a comparative example. Fig. 6 is a schematic view showing a compound semiconductor substrate used in the light-emitting element of Comparative Example 2. 21 201131811 [Description of main component symbols] 10 Light-emitting elements 11 Electrodes 100, 200, 300 Compound semiconductor substrates 101, 201, 301 n-type GaP substrate 103 ' 203' 303 n-type cladding layers 104, 204, 304 live ten levels 105, 305 barrier layer 106, 206, 306 retardation layer 107, 207, 307 p-type cladding layer 108 illuminating ^ 109, 209, 309 p-type GaP layer 110, 210, 310 p-type GaP window layer 22