The Study of Junction Temperature of High Power GaN Light Emitting Diodes 黃文祥、廖豐標
E-mail: [email protected]
ABSTRACT
LED (Light Emitting Diode) is one of the photo-electronic devices for P-N semiconductor materials of associative. There are many good selling points for LED such as small size, long lifetime, low consume electric, response fast. Therefore, LED products are getting more and more popular. Except for traffic sights and outdoor-boards, high-power LEDs gain territory in the applications of the back-lighting systems and solid-state illumination. High-power LEDs requiring high currents drive generate much heat, relatively the temperature of active region control extremely important, because the heat generated in the active layer region would increase more and more, leading to degradation in illumination efficiency and reliability. Therefore, representing the high power of light emitting diodes and high efficiency at the same time, the temperature of active region must be paid attention to too. To evaluate the heat management system, a precise measurement system for junction temperatures of light emitting diodes is highly desirable. We applied the forward voltage method to measure the junction temperature of light emitting diodes and developed an automatic measurement system for the junction temperature of light emitting diodes. So, this thesis depicts importance for the junction temperature of high-power LEDs, and demonstrated that advantages of characterization of junction temperature by using the forward voltage method.
Keywords : Junction Temperature ; Forward Voltage Method ; Light-Emitting Diode Table of Contents
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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