高亮度發光二極體晶圓接合製程之研究

Abstract

高亮度發光二極體晶圓接合製程之研究 研究生:侯智元 指導教授:吳耀銓 博士 國立交通大學材料科學與工程研究所 摘 要 在本篇論文中，將探討磷化鋁鎵銦(AlGaInP)四元合金發光二極體(Light Emitting Diode; LED)與透明基板之晶圓接合(Wafer Bonding)接合介面性質的研究。我們選擇了氧化銦錫薄膜(ITO)來作為晶圓接合的中間媒介層。氧化銦錫薄膜(ITO)是一種透明且具有導電性薄膜，為氧化銦(In2O3)和氧化錫(SnO2)的混合物，(In2O3：SnO2 ＝90%：10% 重量百分比)，一般而言氧化銦錫薄膜(ITO)在膜厚2800A°下的電阻率約為2×10-4 W cm(金屬為 ∼ 10-6 Wcm），可見光穿透率約為90%。 本實驗是以電子束蒸鍍法將氧化銦錫薄膜(ITO)鍍在N型砷化鎵(GaAS)基板上。另外將另一片N型砷化鎵(GaAs)基板以金屬有機氣相沈積(MOCVD)的方式成長上N型磷化銦鎵(InGaP)的磊晶膜。在經過晶片清洗後，兩片對接，在保護氣氛或真空下升溫進行高溫接合的工作，接合的溫度大約為500∼600℃，加熱時間為40分鐘待降溫之後將試片取出做分析。首先進行接合界面觀察，界面觀察是用光學顯微鏡配合CCD攝影機以擷取接面的紅外線影像，可以觀察不同的溫度下已經接合及未接合面的比例各為多少，並配合掃瞄式電子顯微鏡(SEM)影像觀察接合截面，來觀察細部接合界面的完整性。電性分析，試片的電流-電壓(I-V)特性，可以瞭解接面接合的好壞。不同的接合參數，和不同的晶圓清洗方法，都會有不同的結果。此外，也將證明氧化銦錫薄膜(ITO)，應用於透明基板發光二極體之晶圓接合的可行性。

Wafer Bonding Process for High Brightness LEDs Student: Chih-Yuan Hou Advisor: Yewchung Sermon Wu Department of Material Science and Engineering National Chiao Tung University Abstract The (AlxGa1-x)0.5In0.5P /GaP transparent substrate (TS) light emitting diode (LED) was fabricated by wafer bonding technique. In this study, used indium-tin-oxide (ITO) ( In2O3: SnO2 = 90 wt%: 10 wt% ) thin film as an intermediate layer to do indirect wafer bonding. The Indium-Tin-Oxide (ITO) thin film(~2800Å) exhibit high transmission in the visible region(about 90%), high electrical conductivity(2×10-4 W cm) . In this experiment, bonded n-InGaP/ITO to investigate the bonded interface, the indium-tin-oxide (ITO) thin film was deposited on n-GaAs substrate by electron-beam evaporation, the InGaP was also grown on n-GaAs substrate by metalorganic chemical vapor deposition (MOCVD).The pair of n-InGaP/ITO, bonded in Ar ambient or vacuum at 550 and 600℃ for 40 minutes, the bonded interface have been characterized by scanning electron microscopy (SEM) and IR transmission optical microscopy system. The current-voltage (I-V) characteristics have demonstrated to be result of different bonding temperature, ambient and different wafer clean method. In addition, it will demonstrate the feasibility of Indium Tin Oxide (ITO) used as an intermediate layer applying to wafer bonded transparent substrate light emitting diode.