1250666 玖、發明說明： · 【發明所屬之技術領域】 本發明涉及一種發出輻射之半導體晶片之微結構化之領 域，其涉及產生輻射之半導體層序列之輻射發射面之粗糙 化，特別是薄層發光二極體晶片之發出輻射之半導體層序 列之輻射發射面之粗糙化。 薄膜發光二極體晶片之特徵特別是以下各點： -在其產生輻射之磊晶層序列之面向載體元件之第一主 面上施加或形成一種反射層，其使該磊晶層序列中所產生 馨 之電磁輻射之至少一部份反射回到該磊晶層序列中， -該晶晶層序列所具有之厚度是在20 um之範圍中或更 小’特別是在1 0 u m之範圍中， -在該產生輻射之磊晶層序列之遠離該反射層之第二主 面上具有一種混合結構，其在理想情況下會使磊晶之磊晶 層序列中之光達成一種近似於e r g 〇 d i c之分佈，即，該光 具有一種儘可能ergocHc之隨機雜散分佈特性。 【先前技術】 Φ 薄膜發光二極體晶片之基本原理已描述在I. Schnitzel· et a 1., A p p 1. Phy s. Lett. 63 (16)，18. October 1 993, 2 1 74 -2 1 7 6 中，其所揭示之內容此處作爲參考。 薄膜發光二極體晶片之發射區限制於最外之薄磊晶層序 列之前側之已結構化之射出面，因此幾乎可調整一種 L a m b e r t i c表面輻射器之比例。 【發明內容】 1250666 本發明之目的是提供一種微結構之較佳之製造方法及_ 種具有較佳之光射出性之薄膜發光二極體晶片。 該目的以具有申請專利範圍第1項特徵之方法和以具有 申請專利範圍第7項特徵之方法來達成。依據本方法而_ 成之薄膜發光二極體晶片描述在申請專利範圍第32 中 。 本方法或該薄膜發光二極體晶片之有利之其它實施形式 描述在其它各項申請專利範圍中。 本發明之方法所依據之技術原理特別適用於具有以氮化 物-化合物半導體材料爲主（特別是由氮化物-化合物半導體 材料-系統 InxAlyGamN,其中 OSySl 且 x + ySl 所構成之半導體材料爲主者）之磊晶層序列之薄膜發光二 極體晶片。 特別是上述之半導體層序列目前屬於以氮化物-化合物 半導體材料爲主之半導體層序列所構成之組，其中以磊晶 方式製成之半導體層（其通常具有一種由不同之單一層所 構成之靥序列）含有至少一種單一層，其含有由氮化物-化 合物半導體材料-系統InxAlyGai + yN，其中OSxSl， 1且x + yg 1所構成之材料。 上述之半導體層序列例如可具有一種傳統之ρ η -接面， 雙異質結構，單一量子井結構（SQW·結構）或多重量子井結 構（M Q W -結構）。這些結構已爲此行之專家所知悉，此處 因此不再詳述。以GaN爲主之多重量子井結構之一種例 子已描述在W〇01/39282 A2中，其所揭示之內容此處作 1250666 爲參考。 本發明之薄膜發光二極體晶片用之半導體層序列之發出 輻射之面之微結構化所用之方法以下述之基本構想來構 成：在針對生長條件已最佳化之生長基板上以磊晶方式生 長該半導體層序列-且在該半導體層序列上形成-或施加鏡 面層之後，使該半導體層序列由該生長基板分離。該分離 過程在該半導體層序列之分離區中進行，該半導體層序列 至少一部份被分解，使該半導體層序列之分離面（由此使 該基板分離）上仍保留該分離區之成份（特別是分離層之金 屬成份）之異向性殘渣。 然後對該半導體層序列之分離面（其上存在著殘渣）在一 種預蝕刻步驟中使用該殘渣作爲蝕刻遮罩藉由乾燥蝕刻方 法和氣體形式之蝕刻劑或藉由濕式化學蝕刻劑來進行蝕刻 使材料被剝除。較佳是同時使殘渣至少被去除一大部分， 即，異向性之殘渣只暫時用作蝕刻遮罩。 在該分離步驟之後各殘渣大部份保留在該分離面上而成 爲一般之具有可變厚度之層或成爲具有島形-或網形之區 域（其具有中間區），其中該半導體層序列之表面已露出。 在該預蝕刻步驟中，該半導體層序列依據殘渣之層厚度 而受到不同程度之蝕刻，使該半導體層序列之分離面被粗 糙化。 在一種較佳之實施形式中，使該半導體層序列之不同之 晶體多角形平面裸露。特別有利的是在該分離面之預蝕刻 之後以一種再飩刻步驟利用濕式化學-或氣體形式之蝕刻 1250666 劑來對該分離面進行處理，該蝕刻劑主要是在晶體缺陷上 進行蝕刻且在該半導體層序列之分離面上選擇性地對不同 之晶偷多角形平面進行蝕刻。特別有利的是：該濕式化攀 蝕刻劑含有KOH。例如，一種腐蝕性之氣體（H或c丨）適合 用作k體形式之蝕刻劑。Η較佳是可在較高之溫度中用作 蝕刻氣體，特別是溫度大於或等於8〇〇〇c時。 在該半導體層序列由該生長基板分離時只有一些非主要 之殘渣仍留在該分離面上及/或能以一種蝕刻劑使至少大 部份之殘渣被去除時，其中該蝕刻劑主要是在該半導體靨 序列之晶體缺陷上進行蝕刻且選擇性地在該分離面上對不 同之晶體多角形平面進行蝕刻，則在此種情況下上述之預 蝕刻步驟可省略。 在具有氮化物-化合物半導體材料之分離面中較‘佳是使 該分離面分解，使產生氣體形式之氮。此處特別是可使用 一種雷射剝離方法作爲該分離方法。此種雷射剝離方法例 如已描述在 W〇98/14986 A1中，其所揭示之內容此處作 胃參考。另外亦可使用其它分離方法，其中在分離面上保 胃著該分離層之特別是金屬成份之異向性殘渣。 有利的是該半導體層序列在該分離面上具有一種較該半 導體層序列之配置於該分離面之後（由基板觀看時）之部份 _高之缺陷密度。該分離面較佳是位於該半導體層序列之 生長基板和射産生區Z間之緩衝層中。 該緩衝層是該半導體層序列之一種面向基板之半導體 層，其用來製造一種最佳化之生長表面以便隨後可生長該 1250666 半導體層序列之各功能層（例如，一種多重量子井結構）。 此種緩衝層例如可補償該基板之晶格常數和該半導體層序 列之晶格常數之間之差異以及可補償基板之晶體缺陷。藉 由該緩衝層，則同樣可適當地調整各應力狀態以生長該半 導體層序列。 該分離區特別有利的是具有GaN且在該半導體層序列 之分離面上較佳是仍保留著由金屬鎵所構成之異向性殘 渣。 該半導體層序列之存在著該分離區之此區域之ί爹雜濃度 較佳是介於1 * 1 0 18 c m ·3 (含）和1 * 1 〇 19 C m ·3 (含）之間。在此種 情況下該半導體層序列在其分離面上可有利地具有一種介 於l*1018cm·3(含）和1 * 102Gcm·3(含）之間之摻雜濃度。這樣 可使該半導體層序列上之歐姆接觸區較簡易地形成。若該 區域以GaN爲主，則較佳是使用矽作爲摻雜材料。 在另一有利之實施形式中，該分離區含有 A1 GaN，須選 取其 A1-含量，使其在該半導體層序列由該生長基板分離 時可被分解且使A1燒結至該半導體層序列中。該A1_含量 較佳是介於1 %和1 〇 %之間，特別是介於1 %和7 %之間。 爲了製造一種Α1-η-接觸區，則在分離過程中較佳是使A1 熔化且燒結至該半導體層序列中。特別有利的是使用雷射 剝離方法，其中雷射所具有之波長小於360 nm，較佳疋 在3 5 0 11 m (含）和3 5 5 n m (含）之間。 在本方法之另一有利之形式中，該分離區具有GaN_層， 由基板觀看時一種A1 G a N -層連接至該G a N -層。在半導體 -10- 1250666 層序列由該生長基板分離日寺，整自Ga關和—部份之 AlGaN-層會分解。這樣所具有之優點是：由於層品質或其 它原因而需要時，首先可生長—s __層，其較該分離 在該分離過程中，該 部份被分解，這樣若需 區還薄且在該分離過程中被分解 GaN -層和其上方之AlGaN -層之一 要時可達成上述之優點 該AlGaN-層此處較佳是另具有 特別是介於1 %和7 % 一種A卜含量，其介於1 %和1 〇 %之間 之間。 車乂 ί土 7H使用&寶石基板作爲生長基板，其可有利地在電 磁輻射之大的波長範圍中被良好地透過。藍寶石特別是可 透過小於3 5 0 nm之波長，這對GaN或以GaN-爲主之材之 分解是較重要的。 在下一步驟中，在該半導體層序列之已微結構化之分離 面上施加一種接觸墊，特別是一種接觸金屬層以與該半導 體層序列形成電性連接。傳統之習知之金屬層，例如，TiAl-, A1-或TiAlNiAu -接觸區，適合此目的。 特別有利的是藉由半導體層序列之分離面上之微結構而 產生一種依比例（即，具有該結構之尺寸）之粗糙度，其對 應於該半導體層序列在操作時所產生之電磁輻射之波長範 圍（相對於晶片內部之波長而言）。 在以六角形之氮化物-化合物半導體材料系統IbAlyGa^ x_yN，其中O^xSl，0 ^ y = 1且x + ySl所構成之半導體材 料爲主之半導體層序列中使用本方法時特別有利’其中該 0 00 -1-晶體面（六角形之氮化物晶格之心面）是面對該生長 1250666 基板。 該半導體層序列之磊晶生長較佳是藉由 MOVPE (m e t a 11 〇 r g a η 1 s c h e r G a s p h a s e n e p i t a X 1 e)來達成。 可施加一種布拉格鏡面作爲鏡面層。另一方式是可製成 一種鏡面層，其具有一種可透過輻射之層及一由該半導體 層序列觀看時配置於其後之反射層。 該鏡面層同樣可具有一種反射層，其具有多個朝向該半 導體層之視窗且在視窗中配置一種與該反射層不同之電流 輸送層。 依據本發明之方法所製成之發出電磁輻射之半導體晶片 具有至少一以磊晶製成之半導體層序列，其包含：η -導 電之半導體層，Ρ -導電之半導體層和一配置在該二個半 導體層之間之發出電磁輻射之區域。至少一個半導體層含 有氮化物-化合物半導體材料且該半導體層序列以遠離該 半導體層序列之已微結構化之面之此側（即，配置著該鏡 面之此側）而安裝在一載體上。在該半導體晶片之另一實 施形式中，該鏡面層亦被微結構化。 在本方法之一種實施形式中，在該剝離步驟之後例如藉 由雷射剝離方法由分離區之金屬材料所構成之一般之層不 是完全保留在該半導體層序列上，而是只有由金屬材料所 構成之網狀形或島形之結構才保留在該半導體層序列上， 該結構在隨後之預蝕刻步驟中至少幾乎轉印至該半導體層 序列上，以便專門爲該再蝕刻步驟提供不同之晶體多角形 平面。在該再蝕刻步驟中，該蝕刻劑選擇性地作用在不同 1250666 之晶體多角形平面上且因此使該半導體層序列之該分離面 ， 形成一種微觀之粗糙化。來自該預蝕刻步驟之鈾刻邊緣和 半導體層序列中其分離面上之晶體缺陷因此用作蝕刻胚 源。 半導體層序列上之鏡面層（其使半導體層序列在操作時 所產生之輻射之至少一部份反射回到該半導體層序列中） 之形成或施加可在該半導體層序列被微結構化之前或之後 進行，其中第一種方式特別有利。申請專利範圍第1和7 項中該分離步驟（c)之前相對應之步驟之名稱未明確地定 0 出，該步驟必須在該半導體層由基板分離之前及在該微結 構化之前進行。但該鏡面層是該薄膜發光二極體之一種主 要組件。該鏡面層亦可與該半導體層序列用之一種載體一 起與已微結構化之該半導體層序列相連。 本發明基本上不限於使用在薄膜發光二極體中，而是可 廣泛地用在下述場合中，即：在以磊晶製成之已由該生長 基板分離之半導體層序列上需要已微結構化之表面之場合 中。 鲁 【實施方式】 本發明之方法和發光二極體晶片之其它優點和較佳之實 施形式以下將依據第1 a至3b圖中所示之實施例來描述。 在各貫施例和圖式中，相同或作用相同之組件以相同之 穸考符號來表示。各層之厚度未依比例來顯示。反之，爲 了更容易了解之故，各層之厚度顯示成較原來者還大。各 為晶層亦未以正確之厚度比例來顯示。 -13- 1250666 在第1 a至1 e圖中所示之方法流程中，首先在一種由藍 寶石所構成之生長基板1上藉由金屬有機氣相磊晶（MOV PE) 方法而生長一種半導體層序列。該半導體層序列由該藍寶 石基板1開始而具有以下之依序配置之層（請比較第la 圖）： -Si-摻雜之GaN-緩衝層2， -Si-摻雜之GaN-接觸層3(—部份可屬於該緩衝層）， -Si -摻雜之GaN -外罩層4， -產生電磁輻射（特別是綠光或藍光）之層5，其多重量子 井結構具有多個InGaN-量子井和介於其間之GaN-位障 層， -P-摻雜之AlGaN-外罩層6(例如，以Mg作爲p-摻雜材 料）。 該ρ-ί爹雜之AlGaN -外罩層6較佳是仍有一種p -慘雜之 GaN-層（例如，同樣以Mg來摻雜）。 該接觸層3另一方式是可具有Si: AlGaN。 上述之多重量子井結構例如已插述在W〇01/39282 A2 中，其所揭示之內容此處作爲參考。 亦可使用單一量子井結構，雙異質結構或單異質結構以 取代該多重量子井結構。 在該半導體層序列1 0 0上施加〜種金屬鏡面層7，其設 s十成使其可將該活性層中所產生之電磁輻射反射回到該半 導體層序列100中。A1或Ag適合用作藍色光譜區中之鏡 面材料。在使用Ag時該鏡面層以薄的T】_，pt_層作 -14- 1250666 ' 爲襯底。這樣特別是可使該A g -層較佳地黏合在該半導體 層序列1 0 0上。此種黏合促進層之厚度較佳是小於1 n m。 另一方式是可施加一種布拉格鏡面以作爲鏡面層7或製 成一種鏡面層，其具有一種可透過輻射之例如由IT◦所構 成之層及一種由該半導體層序列觀看時配置於其後之反射 層。該鏡面層同樣可具有一種反射層，其具備多個面向該 半導體層序列1 00之視窗，且在視窗中配置一種不同於該 反射層之電流輸送層。 該半導體層序列隨後以該鏡面側而與導電之載體1 0相 連接，該載體例如由GaAs，Ge或Mo所構成。這例如藉由 共晶之連結（其藉由AuGe，AuSn或Pdln來進行）來達成。 但亦可利用焊接或黏合來達成。該藍寶石-基板1然後藉 由一種雷射-剝離方法（其在第1 b ‘圖中以箭頭來表示）來分 離，其中須使該緩衝層2分解，使產生氣體形式之氮且由 金屬鎵所構成之殘渣20以層厚度可變之異向（anisotropic) 層形式而保留在該半導體層序列1 〇 〇上。於此可比較第1 c ®。相對應之雷射-剝離方法描述在W〇9 8 / 1 4 9 8 6 A 1中， 其所揭示之內容此處作爲參考。 該殘渣20隨後在一預蝕刻步驟中以一種蝕刻劑120(其 以材料剝除之方式來對金屬G a和以S i -摻雜之G a N -接觸 層3進行蝕刻）來去除。該以Sl-摻雜之GaN-接觸層3之表 面因此被粗糙化。由金屬鎵所構成之異向性分佈之殘渣此 處用作暫時性之蝕刻遮罩。 在該預蝕刻步驟中較佳是以濕式化學方式來進行蝕刻， -15- 1250666 已稀釋之特殊之KOH適合用作飩刻劑。在本發明之特別 有利之形式中，在該蝕刻步驟中於窆溫時使用一種濃度是 5 %之Κ Ο Η，其中蝕刻期間是5分鐘至1 5分鐘。 另一方式是一種乾鈾W步驟（RIΕ〜方法）例如亦適用於該 預蝕刻步驟中。通常須進行一種預蝕刻步驟，使本發明中 該殘澄之形式可轉移至其下方之半導體層中且因此可使該 半導體層粗糙化。 在本發明之另一形式中，使用一種腐蝕氣體（例如，Η 或C1)作爲蝕刻劑，較佳是在較高之溫度中進行，其特別 是大於或等於800GC。 在上述之例子中，整個緩衝層2在雷射—剝離方法期間 被分解，使其形成一種分離區。另一方式是可使該緩衝層 2和該雷射-剝離方法互相調整，使只有一種分離區在該緩 衝層中分解或在該緩衝層之附近（其較該緩衝層還薄）中分 解。 在該預蝕刻步驟中使該接觸層3之不同之晶體多角形平 面裸露。然後該接觸層3之已預蝕刻之平面在一種再蝕刻 步驟中以另一種濕式化學蝕刻劑來處理（這藉由以一參考 符號1 3 0表示之箭頭來表示），其主要是在晶體缺陷上進 行蝕刻且在該半導體層序列之分離面上選擇性地對不同之 晶體多角形平面進行蝕刻（請參閱第1 d圖）。另一濕式化 學蝕刻劑例如包含Κ Ο Η。藉由以K〇Η來進行之處理，則 該接觸層之表面可很有效地被粗糖化；預鈾刻時所產生之 粗糙度可大大地改良該輻射發出時之效率。 1250666 &再蝕刻步驟中較佳是使用濃縮形式之K0H作爲蝕刻 劑。在本發明之另一較佳之形式中，使用濃度25 %之K〇H 在溫度介於7(^(:和90°C之間（例如，在8(^0時進行蝕刻， 其中蝕刻時間是在3分鐘和1 〇分鐘之間。 另一方式是在該再蝕刻步驟中使用一種腐蝕氣體（例 如，Η或C)作爲飽刻劑。 第2a圖顯示該乾燥蝕刻之後之表面。第2b圖是以κ〇Η 來進行另一蝕刻之後之表面。 爲了使該粗糙作用改良，則該接觸層3至少在面向該緩 衝層2之此側上具有一較隨後之各層4，5和6還高之缺 陷密度。 另外’該接觸層3至少在面向該緩衝層之此側上所具有 之Si摻雜濃度介於含）和m〇19cm.3(含）之間。 這樣可使該接觸層3上之歐姆接觸區之製造簡化。 在另一種實施形式中，GaN-緩衝層2較該以雷射-剝離 方法所分解之層之厚度還薄且該接觸層3之A1-含量至少 在一種面向該緩衝層2之區域中是介於1 %和7 %之間。該 接觸層.3之此區域在進行雷射-剝離時形成氣體形式之氮 和金屬G a及A1之情況下被分解，且A1被熔化而燒結至 仍保留之接觸層3中。 以上述方式可在G a N -接觸層3上產生一種鋁-n _接觸區。 在該G a N -接觸層3之已微結構化之面上然後施加一種 連結墊（特別是連結墊-金屬層）以對該半導體層序列丨〇〇之 11〜側形成一種電性連接（第1 e圖），其例如具有T i A!。 -17- 1250666 藉由該接觸層3之微結構化而產生以一種尺寸爲主之粗 · 糙區，該尺寸對應於電磁輻射之可見光譜之藍色光譜區。 各粗糙結構之大小特別是在該活性之半導體層5中所產生 之電磁輻射之內部半波長之數量級範圍中。 在藉由Μ〇V P E來生長該嘉晶層序列時，該0 0 0 - 1結晶 面（六角形之氮化物晶格之Ν -面）較佳是面向藍寶石-生長 基板。 使用一種波長介於3 5 0 n m和3 6 0 n m之間或更短之雷射 輻射源作爲雷射-剝離方法用之輻射源。 · 在該載體1 0之遠離半導體層序列1 〇〇之此側上在其與 該半導體層序列1 〇 〇相連接之前或之後施加一種接觸層1 2 以便與薄膜發光二極體晶片2 0形成電性上之連接，如第1 e 圖中之一部份所示。該接觸層例如由A1或Τι/Al-層序列 所構成。 在本方法之另一實施形式中，在該鏡面層與載體相 連接之則以類似於該接觸層3之尺寸使該鏡面層被微結構 化。 φ 在本方法之另一實施形式中，在進行雷射剝離之後金屬 Ga或可能仍存在之A1之完全連續之層未保留在該接觸層 3上，而是只有金屬Ga或可能仍存在之A1之殘渣之網狀_ 或島狀之結構（其在下一預蝕刻步驟中至少幾乎轉移至該 接觸層3中）保留在該接觸層3上，以便在隨後之K〇H-蝕 刻中可提供不同之晶體多角形平面。 又，如上所述，一種乾燥蝕刻方法（RIE_方法）或濕式化 -18 ‘ 1250666 學蝕刻方法（較佳是以稀釋形式之K0H來進行）適合用作預· 蝕刻步驟，其中KOH在室溫時例如濃度是5 % ;蝕刻時間 是5至1 5分鐘。 在隨後之再蝕刻步驟中，較佳是使用KOH，特別是如上 所述使用較濃形式之K 〇 Η。 Κ〇Η 擇性地作用在不同之晶體多角形平面上且因此造 成一種藏微式粗糖區。前述pj Ε _過程中之触刻邊緣和該接 觸層中-或該緩衝層2之可能仍保留之區域（若其在雷射剝 離中未完全分解時）中之晶體缺陷用作蝕刻胚源。 鲁 另一方式是在該再蝕刻步驟中可使用腐飽性氣體（例 如’ Η或C1)作爲蝕刻劑’較佳是在較高之溫度中進行， 例如，特別是大於或等於8 0 0Q C時進行。 第3a至3e圖所示之實施例不同於第h至ie圖中者且 其不同之處特別是：在雷射剝離1 1 〇 (第3 b圖）時幾乎不會 或根本不會有金屬（}3或可能仍存在之幻之殘渣留在該接 觸層3上且直接在該雷射剝離1 1 〇之後該接觸層3以含有 KOH之蝕刻劑（較佳是具有如上所述之較濃之形式）來蝕刻 _ (以第3 c圖中之箭頭1 3 0來表示）。 當然若適當時可在蝕刻之前以ΚΟΗ來進行預鈾刻，以 便使不同之晶體多角形平面及/或-缺陷裸露出來，或如上 所述使用一種腐蝕性氣體（例如，Η或C1)作爲蝕刻劑。 就像以上第1 a至1 e圖所示之實施例一樣，另一方式是 在該基板1分離之後該緩衝層2之殘餘層保留在該接觸層 3上，若其較其在分離步驟時已分解之區域還厚時。該粗 -19- 1250666 糙區然後產生在該緩衝層2之殘餘層上。 本發明以上依據各實施例之描述當然不是對本發明之一 種限制。反之，特別是以下之全部之方法都屬本發明之範 圍，即：一種半導體層之分離面在該半導體層之材料已由 該生長基板剝離之後藉由一種缺陷蝕刻而被微結構化。 【圖式簡單說明】 第1 a至1 e圖第一實施例之方法流程之圖解。 第2a，2b圖 該實施例之方法中不同階段時半導體表面1250666 发明, DESCRIPTION OF THE INVENTION: FIELD OF THE INVENTION The present invention relates to the field of microstructured semiconductor wafers that emit radiation, which relates to the roughening of radiation emitting surfaces of radiation-emitting semiconductor layer sequences, in particular thin layers Roughening of the radiation emitting surface of the radiation-emitting semiconductor layer sequence of the light-emitting diode chip. The thin-film light-emitting diode wafer is characterized in particular by the following points: - applying or forming a reflective layer on the first main surface of the carrier-facing element of the radiation-emitting epitaxial layer sequence, which causes the epitaxial layer sequence to At least a portion of the electromagnetic radiation that produces sensation is reflected back into the epitaxial layer sequence, - the crystallographic layer sequence has a thickness in the range of 20 um or less, especially in the range of 10 um - having a hybrid structure on the second major surface of the radiation-emitting epitaxial layer sequence remote from the reflective layer, which ideally causes the light in the epitaxial epitaxial layer sequence to approximate an erg 〇 The distribution of dic, that is, the light has a random stray distribution characteristic of ergocHc as much as possible. [Prior Art] The basic principle of the Φ thin film light-emitting diode chip has been described in I. Schnitzel et al., A pp 1. Phy s. Lett. 63 (16), 18. October 1 993, 2 1 74 - In 2 1 7 6 , the disclosure thereof is hereby incorporated by reference. The emission region of the thin film light-emitting diode wafer is limited to the structured exit surface on the front side of the outermost thin epitaxial layer sequence, so that the ratio of a L a m b e r t i c surface radiator can be adjusted. SUMMARY OF THE INVENTION 1250666 An object of the present invention is to provide a preferred method of fabricating a microstructure and a thin film light emitting diode wafer having better light exiting properties. This object is achieved by a method having the features of the first aspect of the patent application and by a method having the features of the seventh aspect of the patent application. A thin film light-emitting diode wafer according to the present method is described in the 32nd patent application. Advantageous further embodiments of the method or of the thin-film light-emitting diode wafer are described in the scope of the other patent applications. The technical principle according to the method of the present invention is particularly suitable for a semiconductor material mainly composed of a nitride-compound semiconductor material (particularly a nitride-compound semiconductor material-system InxAlyGamN, wherein OSySl and x + ySl are dominant). a thin film light emitting diode wafer of an epitaxial layer sequence. In particular, the semiconductor layer sequence described above currently belongs to the group consisting of a nitride-compound semiconductor material-based semiconductor layer sequence, wherein the semiconductor layer is formed by epitaxy (which usually has a single layer composed of different layers). The ruthenium sequence) contains at least one single layer containing a material composed of a nitride-compound semiconductor material-system InxAlyGai + yN, wherein OSxSl, 1 and x + yg 1 . The semiconductor layer sequence described above may have, for example, a conventional ρ η - junction, a double heterostructure, a single quantum well structure (SQW·structure) or a multiple quantum well structure (M Q W - structure). These structures are known to experts in this field and will not be described here. An example of a GaN-based multiple quantum well structure has been described in WO 01/39282 A2, the disclosure of which is incorporated herein by reference. The method for the microstructure of the radiation-emitting surface of the semiconductor layer sequence for a thin film light-emitting diode wafer of the present invention is constructed in the following basic concept: in an epitaxial manner on a growth substrate optimized for growth conditions After growing the semiconductor layer sequence - and forming - or applying a mirror layer on the semiconductor layer sequence, the semiconductor layer sequence is separated from the growth substrate. The separation process is carried out in a separation region of the semiconductor layer sequence, at least a portion of which is decomposed such that the separation surface of the semiconductor layer sequence (and thereby the substrate is separated) still retains the composition of the separation region ( In particular, the anisotropic residue of the metal component of the separation layer. The separation surface of the semiconductor layer sequence (the residue is present thereon) is then used as a etch mask in a pre-etching step by a dry etching method and a gas form etchant or by a wet chemical etchant. Etching causes the material to be stripped. Preferably, the residue is at least removed a large portion at the same time, i.e., the anisotropic residue is only temporarily used as an etch mask. After the separation step, a large portion of the residue remains on the separation surface to become a layer having a generally variable thickness or a region having an island shape or a network shape (having an intermediate portion), wherein the semiconductor layer sequence The surface has been exposed. In the pre-etching step, the semiconductor layer sequence is etched to varying degrees depending on the thickness of the layer of the residue, so that the separation surface of the semiconductor layer sequence is roughened. In a preferred embodiment, the different crystal polygonal planes of the semiconductor layer sequence are exposed. It is particularly advantageous to treat the separation surface by a wet chemical- or gaseous etching of 1250666 after a pre-etching of the separation surface, the etching agent being primarily etched on the crystal defects and The different polygonal planes are selectively etched on the separation surface of the semiconductor layer sequence. It is particularly advantageous if the wet etchant contains KOH. For example, a corrosive gas (H or c丨) is suitable as an etchant in the k-body form. Preferably, Η is used as an etching gas at a higher temperature, especially when the temperature is greater than or equal to 8 〇〇〇c. When the semiconductor layer sequence is separated from the growth substrate, only some non-primary residues remain on the separation surface and/or at least a majority of the residue can be removed with an etchant, wherein the etchant is mainly The crystal defects of the semiconductor germanium sequence are etched and the different crystal polygonal planes are selectively etched on the separation surface. In this case, the pre-etching step described above may be omitted. In the separation face having the nitride-compound semiconductor material, it is preferable to decompose the separation surface to produce nitrogen in the form of a gas. In particular, a laser stripping method can be used here as the separation method. Such a laser stripping method is described, for example, in WO 98/14986 A1, the disclosure of which is incorporated herein by reference. Alternatively, other separation methods may be used in which an anisotropic residue of the separation layer, particularly a metal component, is retained on the separation surface. Advantageously, the semiconductor layer sequence has a defect density on the separation surface that is higher than a portion of the semiconductor layer sequence disposed after the separation surface (when viewed from the substrate). Preferably, the separation surface is located in a buffer layer between the growth substrate and the shot generation region Z of the semiconductor layer sequence. The buffer layer is a substrate-oriented semiconductor layer of the semiconductor layer sequence that is used to fabricate an optimized growth surface for subsequent growth of the functional layers of the 1250666 semiconductor layer sequence (e.g., a multiple quantum well structure). Such a buffer layer, for example, compensates for the difference between the lattice constant of the substrate and the lattice constant of the semiconductor layer sequence and compensates for crystal defects of the substrate. With this buffer layer, the respective stress states can be appropriately adjusted to grow the semiconductor layer sequence. It is particularly advantageous for the separation zone to have GaN and preferably retain an anisotropic residue of metal gallium on the separation side of the semiconductor layer sequence. The concentration of the semiconductor layer in the region of the separation region is preferably between 1 * 1 0 18 c m · 3 (inclusive) and 1 * 1 〇 19 C m · 3 (inclusive). In this case, the semiconductor layer sequence advantageously has a doping concentration between 1*1018 cm·3 (inclusive) and 1*102 Gcm·3 (inclusive) on its separation surface. This makes it easier to form an ohmic contact region on the semiconductor layer sequence. If the region is predominantly GaN, it is preferred to use germanium as the dopant material. In a further advantageous embodiment, the separation zone contains A1 GaN, the A1-content of which must be chosen such that it can be decomposed and the A1 sintered into the semiconductor layer sequence when the semiconductor layer sequence is separated from the growth substrate. The A1_ content is preferably between 1% and 1%, especially between 1% and 7%. In order to produce a Α1-η-contact region, it is preferred that A1 is melted and sintered into the semiconductor layer sequence during the separation process. It is particularly advantageous to use a laser lift-off method in which the laser has a wavelength of less than 360 nm, preferably between 3 5 0 11 m (inclusive) and 3 5 5 n m inclusive. In another advantageous form of the method, the separation zone has a GaN-layer to which an A1 G a N - layer is attached when viewed from the substrate. In the semiconductor -10- 1250666 layer sequence, the eclipse is separated from the growth substrate, and the AlGaN-layer from the Ga-off and the partial-decomposition is decomposed. This has the advantage that the layer of s___ can be first grown due to layer quality or other reasons, which is decomposed during the separation process, so that the area is thin and The above-described advantages can be achieved by decomposing the GaN-layer and one of the AlGaN-layers above it during the separation process. The AlGaN-layer preferably has an A content of, in particular, between 1% and 7%. It is between 1% and 1%. The rut soil 7H uses & gem substrate as a growth substrate, which can be favorably transmitted in a large wavelength range of electromagnetic radiation. Sapphire, in particular, can transmit wavelengths less than 350 nm, which is more important for the decomposition of GaN or GaN-based materials. In the next step, a contact pad, in particular a contact metal layer, is applied to the microstructured separation surface of the semiconductor layer sequence to form an electrical connection with the semiconductor layer sequence. Conventional conventional metal layers, such as TiAl-, A1- or TiAlNiAu-contact regions, are suitable for this purpose. It is particularly advantageous to produce a scale (i.e. having the dimensions of the structure) by the microstructure on the separation surface of the semiconductor layer sequence, which corresponds to the electromagnetic radiation generated during operation of the semiconductor layer sequence. The wavelength range (relative to the wavelength inside the wafer). It is particularly advantageous when the method is used in a semiconductor layer sequence mainly composed of a semiconductor material composed of a hexagonal nitride-compound semiconductor material system IbAlyGa^ x_yN, wherein O^xSl, 0 ^ y = 1 and x + ySl The 0 00 -1- crystal face (the hexagonal nitride crystal lattice of the heart) is facing the growth of 1250666 substrates. The epitaxial growth of the semiconductor layer sequence is preferably achieved by MOVPE (m e t a 11 〇 r g a η 1 s c h e r G a s p h a s e n e p i t a X 1 e). A Bragg mirror can be applied as a mirror layer. Alternatively, a mirror layer can be formed having a radiation transmissive layer and a reflective layer disposed behind the semiconductor layer sequence. The mirror layer can likewise have a reflective layer having a plurality of windows facing the semiconductor layer and having a different current transport layer disposed in the window than the reflective layer. The semiconductor wafer emitting electromagnetic radiation produced by the method of the present invention has at least one semiconductor layer sequence formed by epitaxy, comprising: an η-conductive semiconductor layer, a Ρ-conductive semiconductor layer and a second The area between the semiconductor layers that emits electromagnetic radiation. At least one of the semiconductor layers contains a nitride-compound semiconductor material and the semiconductor layer sequence is mounted on a carrier on the side of the microstructured face away from the sequence of semiconductor layers (i.e., the side on which the mirror is disposed). In another embodiment of the semiconductor wafer, the mirror layer is also microstructured. In one embodiment of the method, the general layer of the metal material of the separation zone, for example by the laser stripping method after the stripping step, is not completely retained on the semiconductor layer sequence, but only by the metal material. The mesh-shaped or island-shaped structure is retained on the semiconductor layer sequence, and the structure is at least almost transferred to the semiconductor layer sequence in a subsequent pre-etching step to specifically provide different crystals for the re-etching step. Polygonal plane. In the re-etching step, the etchant selectively acts on different polygonal planes of 1250666 and thus causes the separation surface of the semiconductor layer sequence to form a microscopic roughening. The crystal defects from the uranium engraved edge of the pre-etching step and the separation surface thereof in the semiconductor layer sequence are thus used as an etching source. The formation or application of a mirror layer on the sequence of semiconductor layers that causes at least a portion of the radiation generated by the semiconductor layer sequence to be reflected back into the semiconductor layer sequence can be prior to the microstructure of the semiconductor layer sequence being After that, the first way is particularly advantageous. The names of the corresponding steps before the separation step (c) in the first and seventh claims of the patent application are not explicitly determined, and the steps must be performed before the semiconductor layer is separated from the substrate and before the micro-structuring. However, the mirror layer is a major component of the thin film light emitting diode. The mirror layer can also be connected to the microstructured semiconductor layer sequence together with a carrier for the semiconductor layer sequence. The present invention is basically not limited to use in a thin film light-emitting diode, but can be widely used in the case where a microstructure has been required on a semiconductor layer sequence which has been formed by epitaxy and which has been separated by the growth substrate. In the case of the surface. [Embodiment] Other advantages and preferred embodiments of the method and LED array of the present invention will be described below in accordance with the embodiments shown in Figures 1a through 3b. In the respective embodiments and drawings, the same or identical components are denoted by the same reference numerals. The thickness of each layer is not shown to scale. Conversely, for easier understanding, the thickness of each layer is shown to be larger than the original. The respective crystal layers are not displayed in the correct thickness ratio. -13- 1250666 In the process flow shown in Figures 1a to 1e, a semiconductor layer is first grown by a metal organic vapor phase epitaxy (MOV PE) method on a growth substrate 1 composed of sapphire. sequence. The semiconductor layer sequence starts from the sapphire substrate 1 and has the following sequentially arranged layers (please compare the first drawing): -Si-doped GaN-buffer layer 2, -Si-doped GaN-contact layer 3 (a portion may belong to the buffer layer), a -Si-doped GaN-cladding layer 4, a layer 5 that produces electromagnetic radiation (especially green or blue light), the multiple quantum well structure having a plurality of InGaN-quantum Well and intervening GaN-barrier layer, -P-doped AlGaN-cladding layer 6 (for example, Mg as p-doped material). Preferably, the ρ-ί-doped AlGaN-cladding layer 6 still has a p-doped GaN-layer (e.g., also doped with Mg). Another way of the contact layer 3 is to have Si: AlGaN. The multiple quantum well structure described above is for example described in WO 01/39282 A2, the disclosure of which is incorporated herein by reference. A single quantum well structure, a double heterostructure or a single heterostructure can also be used to replace the multiple quantum well structure. A metal mirror layer 7 is applied to the semiconductor layer sequence 100, which is arranged such that electromagnetic radiation generated in the active layer can be reflected back into the semiconductor layer sequence 100. A1 or Ag is suitable for use as a mirror material in the blue spectral region. When Ag is used, the mirror layer is made of a thin T]_, pt_ layer of -14-1250666'. In particular, the A g - layer is preferably bonded to the semiconductor layer sequence 100. The thickness of such an adhesion promoting layer is preferably less than 1 n m. Alternatively, a Bragg mirror can be applied as the mirror layer 7 or as a mirror layer having a layer that is transparent to radiation, such as IT◦, and a layer that is disposed behind when viewed from the semiconductor layer sequence. Reflective layer. The mirror layer may also have a reflective layer having a plurality of windows facing the sequence of semiconductor layers 100, and a current transport layer different from the reflective layer is disposed in the window. The semiconductor layer sequence is then connected to the electrically conductive carrier 10 on the mirror side, which is for example composed of GaAs, Ge or Mo. This is achieved, for example, by eutectic bonding, which is carried out by AuGe, AuSn or Pdln. But it can also be achieved by welding or bonding. The sapphire-substrate 1 is then separated by a laser-peeling method (which is indicated by arrows in Figure 1 b'), wherein the buffer layer 2 is decomposed to produce a gaseous form of nitrogen and is made of metal gallium. The residue 20 is formed on the semiconductor layer sequence 1 in the form of an anisotropic layer having a variable layer thickness. Here, the 1 c ® can be compared. Corresponding laser-peeling methods are described in W 9 8 / 1 4 9 8 6 A 1 , the disclosure of which is hereby incorporated by reference. The residue 20 is then removed in a pre-etching step with an etchant 120 which etches the metal Ga and the Si-doped GaN-contact layer 3 by stripping the material. The surface of the S1-doped GaN-contact layer 3 is thus roughened. The residue of the anisotropic distribution composed of metal gallium is used here as a temporary etching mask. In the pre-etching step, etching is preferably carried out in a wet chemical manner, and -15-1250666 diluted special KOH is suitable as a etchant. In a particularly advantageous form of the invention, a concentration of 5 % Κ Η is used during the tempering step, wherein the etching period is from 5 minutes to 15 minutes. Alternatively, a dry uranium W step (RI Ε ~ method), for example, is also suitable for use in the pre-etching step. It is generally necessary to carry out a pre-etching step in which the residual form of the present invention can be transferred to the underlying semiconductor layer and thus the semiconductor layer can be roughened. In another form of the invention, an etching gas (e.g., Η or C1) is used as the etchant, preferably at a higher temperature, which is particularly greater than or equal to 800 GC. In the above example, the entire buffer layer 2 is decomposed during the laser-peeling process to form a separation zone. Alternatively, the buffer layer 2 and the laser-peeling method may be adjusted to each other such that only one separation region is decomposed in the buffer layer or in the vicinity of the buffer layer (which is thinner than the buffer layer). The different crystal polygonal planes of the contact layer 3 are exposed in the pre-etching step. The pre-etched plane of the contact layer 3 is then treated in another re-etching step with another wet chemical etchant (this is indicated by the arrow indicated by a reference numeral 130), which is mainly in the crystal Etching is performed on the defects and different crystal polygon planes are selectively etched on the separation plane of the semiconductor layer sequence (see Figure 1 d). Another wet chemical etchant, for example, comprises ruthenium iridium. By treating with K〇Η, the surface of the contact layer can be effectively saccharified; the roughness produced by pre-uranium engraving can greatly improve the efficiency at which the radiation is emitted. Preferably, the 1250666 & re-etching step uses a concentrated form of K0H as an etchant. In another preferred form of the invention, a concentration of 25% K〇H is used at a temperature between 7 (^ and 90 ° C (for example, etching is performed at 8 (0), wherein the etching time is Between 3 minutes and 1 minute. Another way is to use an etching gas (for example, Η or C) as a saturating agent in the re-etching step. Figure 2a shows the surface after the dry etching. The surface after another etching is performed by κ 。. In order to improve the roughness, the contact layer 3 has a higher layer 4, 5 and 6 at least on the side facing the buffer layer 2 The defect density. In addition, the contact layer 3 has a Si doping concentration of at least on the side facing the buffer layer and between m〇19 cm.3 (inclusive). The fabrication of the upper ohmic contact region is simplified. In another embodiment, the GaN-buffer layer 2 is thinner than the layer decomposed by the laser-peeling method and the A1-content of the contact layer 3 is at least one The area of the buffer layer 2 is between 1% and 7%. This area of the contact layer .3 is performing laser- When the nitrogen is formed in the form of a gas and the metals G a and A1 are decomposed, the A1 is melted and sintered into the contact layer 3 which remains. The aluminum can be produced on the G a N -contact layer 3 in the above manner. -n _ contact region. Then, a bonding pad (particularly a bonding pad-metal layer) is applied on the microstructured surface of the G a N -contact layer 3 to align the semiconductor layer sequence 11 to the side Forming an electrical connection (Fig. 1 e), which has, for example, T i A! -17- 1250666 by the microstructure of the contact layer 3, a coarse and rough region dominated by one size is produced, the size corresponding to In the blue spectral region of the visible spectrum of electromagnetic radiation. The size of each roughness is in particular in the order of magnitude of the internal half wavelength of the electromagnetic radiation generated in the active semiconductor layer 5. This is grown by Μ〇VPE In the case of the Jiajing layer sequence, the 0 0 0 -1 crystal plane (the hexagonal surface of the hexagonal nitride crystal lattice) is preferably oriented to the sapphire-growth substrate. A wavelength of between 350 nm and 3 60 nm is used. Radiation source between or shorter as a laser-peeling method On the side of the carrier 10 which is remote from the semiconductor layer sequence 1 , a contact layer 1 2 is applied before or after the connection to the semiconductor layer sequence 1 以便 in order to interact with the thin film light-emitting diode wafer 2 0, forming an electrical connection, as shown in one of the figures in Figure 1 e. The contact layer consists, for example, of an A1 or Τι/Al-layer sequence. In another embodiment of the method, the mirror The layer is connected to the carrier such that the mirror layer is microstructured in a manner similar to the size of the contact layer 3. φ In another embodiment of the method, the metal Ga or the A1 that may still be present after laser stripping A completely continuous layer is not retained on the contact layer 3, but rather a mesh-like or island-like structure of metal Ga or a residue of A1 which may still be present (which is at least almost transferred to the contact in the next pre-etching step) Layer 3) remains on the contact layer 3 to provide a different crystal polygonal plane in subsequent K〇H-etching. Further, as described above, a dry etching method (RIE_method) or a wet -18' 1250666 etching method (preferably performed in a diluted form of K0H) is suitable as a pre-etching step in which KOH is in the chamber For example, the temperature is 5% at a temperature; the etching time is 5 to 15 minutes. In the subsequent re-etching step, KOH is preferably used, in particular, the more concentrated form of K Η 如上 is used as described above.择 Selectively acts on different polygonal planes of the crystal and thus creates a micro-sweet sugar zone. A crystal defect in the etched edge of the aforementioned pj Ε _ and the region of the contact layer or which may remain in the buffer layer 2 (if it is not completely decomposed in the laser stripping) is used as an etch source. Another way is to use a suffocating gas (for example, 'Η or C1) as an etchant in the re-etching step, preferably at a higher temperature, for example, especially greater than or equal to 800 ° C Time to proceed. The embodiments shown in Figures 3a to 3e differ from those in Figures h to ie and differ in particular: there is little or no metal at the time of laser stripping 1 1 〇 (Fig. 3b) (}3 or a phantom residue that may still remain on the contact layer 3 and directly after the laser stripping 1 1 该, the contact layer 3 is an etchant containing KOH (preferably having a thicker as described above) In the form of etching _ (indicated by the arrow 1 3 0 in Figure 3 c). Of course, if appropriate, pre-uranium engraving can be performed with germanium before etching to make different crystal polygon planes and/or The defect is exposed, or a corrosive gas (for example, tantalum or C1) is used as an etchant as described above. Like the embodiment shown in Figures 1a to 1e above, another way is to separate the substrate 1 Thereafter, the residual layer of the buffer layer 2 remains on the contact layer 3 if it is thicker than the region which was decomposed during the separation step. The rough -19-1250666 rough region is then produced in the residual layer of the buffer layer 2. The above description of the embodiments in accordance with the present invention is of course not a limitation of the present invention. In particular, all of the following methods are within the scope of the invention, that is, a separation surface of a semiconductor layer is microstructured by a defect etching after the material of the semiconductor layer has been peeled off from the growth substrate. BRIEF DESCRIPTION OF THE DRAWINGS A schematic diagram of the process flow of the first embodiment of Figures 1a to 1e. 2a, 2b shows the semiconductor surface at different stages of the method of this embodiment
之REM-接收情形。 第3 a至3 e圖第二實施例之方法流程之圖解。 主要元件之符號表：REM-receiving situation. An illustration of the method flow of the second embodiment of Figures 3a through 3e. Symbol table of main components:
1 藍寶 石 基 板 2 GaN- 緩 衝 層 3 GaN- 接 觸 層 4 GaN- 外 罩 層 5 產生 電 磁 輻 射 之 層 6 AlGa N- 外 罩 層 7 金屬 鏡 面 層 10 載體 12 接觸 層 20 薄膜 發 光 二 極 體 臼 bir 曰曰/T 100 半導 體 層 序 列 120 腐蝕 劑 -20-1 sapphire substrate 2 GaN-buffer layer 3 GaN-contact layer 4 GaN-cladding layer 5 layer for generating electromagnetic radiation 6 AlGa N- outer cover layer 7 metal mirror layer 10 carrier 12 contact layer 20 thin film light-emitting diode 臼bir 曰曰/ T 100 semiconductor layer sequence 120 corrosive agent-20-