高功率 GaN 發光二極體接面溫度之研究 黃文祥、廖豐標
E-mail: [email protected]
摘 要
發光二極體 (Light Emitting Diode；LED) 為P-N半導體材料結合的光電元件之一，由於LED具有體積小、壽命長、耗電量小
、反應速率快等特性。因此，發光二極體產品在市場上開始受到重視，除了交通號誌燈與大型戶外看板外，高功率發光二 極體也逐漸在LCD背光模組及固態照明等應用中佔有一席之地。 高功率發光二極體需要大電流驅動，相對下發光層的溫 度控制在極為重要，因為在發光主動層高溫會使得發光效率大幅降低，也會影響LED的可靠度。因此，在展現LED的高功 率與高效率同時，發光層的溫度也得注意，這種「二高一低」的要求原則下，將主導LED照明的進化時程。 為有效評估高 功率發光二極體的散熱機制，需要精確量測高功率發光二極體的接面溫度。我們使用順向電壓法量測發光二極體的接面溫 度，並開發完成高功率發光二極體的自動化接面溫度量測系統。因此，在本文中將說明接面溫度對高功率發光二極體的重 要性及以順向電壓法對LED接面溫度的量測的優點。
關鍵詞 : 接面溫度 ; 順向電壓法 ; 高功率發光二極體
目錄
封面內頁 簽名頁 授權書...iii 中文摘要...iv 英文摘 要...v 誌謝...vi 目
錄...vii 圖目錄...ix 表目 錄...xi 第一章 緒論...1 1.1 前 言...1 1.2 研究目的與方法...2 1.3 論文結
構...4 第二章 實驗原理...6 2.1 發光二極體原理及介 紹...6 2.2 半導體材料效應...10 2.2.1 氮化鎵材料特性及發 展...12 2.2.2 直接能隙與間接能隙材料特性...16 2.2.3 溫度對能隙之影 響...17 2.2.4 溫度對波長之影響...18 2.3 發光效率之提升方 式...21 2.3.1 雙異質結構...22 2.3.2 表面粗化重要性及技 術...24 2.4 固晶種類與應用...25 2.4.1 銀膠固
晶...26 2.4.2 共金固晶...27 2.4.3 覆晶固
晶...28 2.5 氮化鎵發光二極體製程技術...29 第三章 實驗方 法...31 3.1 實驗步驟及架構...32 3.2 順向電壓法...
...36 3.3 校正量測 ...40 3.4 實際量
測...43 第四章 實驗樣品製備...45 4.1直流電流造成發光效率衰減 之效應...47 4.2 脈衝電流造成發光效率衰減之效應...48 4.3接面溫度和載子濃度 對LED發光效率衰減的影響...51 4.4 共金與非共金固晶LED接面溫度量測結果...54 4.5 不同 元件結構之銀膠LED接面溫度量測結果...58 第五章 結論...63 參考文 獻...65
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