臺灣博碩士論文加值系統

本論文係針對不同結構的氮化鎵高壓發光二極體進行技術開發與製程之改善研究，在水平式1×8晶粒高壓發光二極體上，我們提出一個製程技術，在每個晶粒的側壁使用濕蝕刻倒角結構來增強高壓發光二極體的光提取新技術。所用的u-GaN層厚度在3-7 μm範圍內，經由Trace-Pro模擬顯示，透過增加u-GaN厚度，可以提高具有倒角結構高壓發光二極體的光提取。沒有倒角結構的高壓發光二極體其輸出功率(@ 80 mA)為538-539.1 mW。然而具有倒角結構的高壓發光二極體其輸出功率(@ 80mA)在3、5和7 μm的u-GaN厚度下分別可增加到555.3、573.1和561.6 mW。在具有7 μm厚的u-GaN層之結構，因為磊晶結構厚度增加很多，容易在濕蝕刻製程中造成蝕刻困難。由於濕蝕刻速率明顯降低，所以時間蝕刻拉長，對於u-GaN層具有7μm厚的磊晶結構，其損傷更為明顯，因此其元件的光萃取略有減少。本研究證實了倒角結構對於提高高壓發光二極體的性能非常有用，特別是對於具有5 μm之u-GaN厚度結構。
在垂直式結構之高壓氮化鎵發光二極體研究方面，我們在銅鎢金屬基板上製作了具有1×4 晶粒結構的元件，我們嘗試了不同的晶粒的幾何圖形以提高其光電性能。由於在晶粒中的電流擴散主要受電極與晶片邊緣之間的距離的影響，當正方形晶粒組合在高壓發光二極體時，由於在電極附近會產生明顯的電流擁擠效應，導致元件發光效率較差，這可歸因於正方形晶粒的電極都遠離邊緣，導致嚴重的電流擁擠現象。反之高壓發光二極體如果由三角形或L形晶粒構成，因為電極靠近晶片的邊緣，電流擴散效果可以很容易地提高。當使用三角形晶粒來製作高壓發光二極體時，與其他晶粒相比，該元件具有優異的光電效率，因為電流擁擠效應更低，發光更均勻。在環氧樹脂封裝製程之後，使用該高壓發光二極體(@ 80mA)獲得14.9 V較低的正向電壓和353.2 mW較高的輸出功率。本研究證實了三角形晶粒的設計有利於提高高壓發光二極體的光電性能。
在覆晶式結構之高壓氮化鎵發光二極體研究方面，我們採用1×4 晶粒製作了三種類型的白光發光二極體，第一種是使用金線接合技術與四個單一晶片串聯的發光二極體。另外兩種元件是使用串連技術的1×4水平式結構和1×4覆晶結構的高壓發光二極體。這三種元件的表面溫度(@ 20 mA)則分別為30.74-31.82、65.93-68.95和27.01-27.96 ℃，顯示透過覆晶結構的元件，可以顯著提高高壓發光二極體的散熱。在100 mA的注入電流下，串聯式高壓發光二極體，水平式高壓發光二極體和覆晶式高壓發光二極體的發光效率分別為80.8、81.0和91.8 lm/W。根據我們的計算，覆晶式高壓發光二極體的發光尺寸只有串聯式高壓發光二極體的84 %，而覆晶式高壓發光二極體的製造可以在沒有金線接合製程的情況下進行，這顯示覆晶式高壓發光二極體具有比串聯式高壓發光二極體更高的光電性能。

目錄
誌謝.................................................... i
中文摘要................................................ ii
Abstract .............................................. iv
目錄....................................................vi
圖目錄.................................................viii
表目錄....................................................x
1-1 前言.................................................1
1-2 文獻回顧..............................................2
1-3 研究背景............................................. 8
1-4 研究動機與目的....................................... 9
第二章 實驗步驟與方法.................................... 11
2-1 傳統高壓發光二極體的製程介紹.......................... 11
2-2 具有側壁倒角結構的GaN/藍寶石高壓發光二極體製程 ........ 12
2-3 在高導熱金屬基板上製作垂直型高壓發光二極體............. 15
2-4 覆晶式高壓發光二極體製程..............................20
2-5 實驗分析設備.........................................24
第三章 利用側壁倒角結構改善GaN/藍寶石高壓發光二極體光取出率..31
3-1 在不同厚度u-GaN on GaN/藍寶石製造側壁倒角結構高壓發光二極體 .....................................................31
3-2 側壁倒角結構GaN/藍寶石高壓發光二極體光萃取率和電流密度分佈….....................................................32
3-3 側壁倒角結構GaN/藍寶石高壓發光二極體的光電性能 ........................................................35
第四章 垂直型高壓發光二極體/銅鎢金屬基板效率差異 ........................................................41
4-1 垂直型高壓發光二極體/銅鎢金屬基板電極差異製程 ........................................................41
4-2 垂直型高壓發光二極體/銅鎢金屬基板的電流密度分佈和光電性能 ........................................................42
4-3 垂直型高壓發光二極體/銅鎢金屬基板的熱特性 ..............47
4-4 垂直型高壓發光二極體/銅鎢金屬基板應用在汽車大燈.........48
第五章 白光覆晶高壓發光二極體製程和信賴度...................53
5-1 白光覆晶高壓發光二極體散熱改善.........................53
5-2 白光覆晶高壓發光二極體光電效率.........................56
5-3 白光覆晶高壓發光二極體應用在照明上的信賴度..............61
第六章 結論與未來工作.....................................63
6-1 實驗結論.............................................63
6-2 未來研究方向.........................................65
參考文獻.................................................66
List of Publications .................................. 70
Other List of Publications ............................ 71

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