臺灣博碩士論文加值系統

摘要

本論文研究的目的，是要開發以矽為材料之金氧半導體發光二極體。我們首先以電子束蒸鍍機來蒸鍍SiOx薄膜，薄膜中的氧含量約為1.1-1.2。對SiOx薄膜進行800℃、900℃與1000℃的退火，使其發生相分離，進而得到由SiO2包覆的奈米矽。相分離的產生可以透過Si-O-Si之stretching vibration band 隨退火溫度的提高往高波數方向移動來驗證。而奈米矽晶體的存在，則可由TEM來觀察。我們發現，在1000℃的退火之後，奈米矽顆粒已形成晶體，其大小約為5nm。此外，退火之後的薄膜，由於其中含有奈米矽顆粒，因此在325nm的光源照射下，能有發光的能力。而其發光光譜會隨著退火溫度的提升而有紅移的現象，這是因奈米矽顆粒變大所造成的結果。

我們亦成功的以電子束蒸鍍機蒸鍍出ITO薄膜，直接鍍出的ITO薄膜透光率與結晶性不佳。但施以550℃、4分鐘之熱處理後，其可見光範圍之平均穿透率大於87%，且電阻值降低至4.36 x 10-4 Ω-cm。

最後，我們成功製做出以SiOx薄膜為發光層，ITO為透明電極之MOSLED，經900℃退火的SiOx~1.2元件，其驅動電壓約為2.6V，達到低驅動電壓的要求。而經1000℃退火之SiOx~1.2元件，則能發出500-700nm之電激發光。我們的成果顯示，透過本文中的方式能成功製造奈米矽發光元件，且能滿足低驅動電壓之要求，並能發出可見光範圍的橘紅光。

Abstract

The aim of this study is to fabricate Si-based MOSLED. The SiOx films are prepared by e-beam evaporation. The oxygen content (x) is in the range of 1.1~1.2.

We have perfeormed thermal annealing on the SiOx films in order to achieve the phase separation is monitered by the evolution of Si-O-Si stretching vibration band which shifts to higher wavenumber when the annealing temperature is increased. The existence of nc-Si is observed by TEM measurement. After the 1000℃ annealing step, nano sized Si are crystallized and it’s mean size is around 5nm. In addition, the annealed SiOx films emit light with excitation at 325nm. It’s PL redshift when the annealing temperature is increased, due to the augmentation of the mean size of nanosize Si.

We have also prepared ITO films by e-beam evaporation. After 550℃, 4min thermal treatemeut, the transmittance of ITO films is about 87% in the visible range and the resistance is 4.36 x 10-4 Ω-cm.

The MOSLED using SiOx~1.2 as emitting layer and ITO as transparent electrode are fabricated. The turn-on voltage of 900℃ annealed SiOx sample is around 2.6V. The 1000℃ annealed SiOx~1.2 sample emits electroluminescence (EL) in the range of 500-700nm (orange light). Our results proved that nano size Si is feasible for MOSLED.

目錄

摘要...............................................................4
英文摘要...........................................................5
目錄...............................................................1
圖目錄.............................................................3
第一章 導論....................................................6
1-1 前言........................................................6
1-2研究動機與目的..............................................7
第二章 理論基礎................................................8
2-1 奈米材料之介紹.............................................8
2-1-1 何謂奈米材料.........................................8
2-1-2 奈米材料之發展史.....................................8
2-1-3 奈米材料之特性......................................10
2-2 發光二極體................................................11
2-2-1 發光二極體之原理....................................11
2-2-2 發光二極體發光原理..................................11
2-3 n型透明導電膜材料........................................14
2-3-1 氧化錫(ITO)特性.....................................14
2-3-2 氧化鋅掺鋁(AZO)特性.................................15
2-4 發光層材料................................................16
2-5 光致螢光發光光譜儀之原理..................................17
2-6 電致發光光譜儀之原........................................19
2-7 霍爾量測之原理....................................... ..19
2-8 FTIR之原理...............................................22
2-9 TEM之原理................................................22
2-10 XPS之原理................................................25
2-11 XRD之原理................................................25
2-12 歐姆接觸.................................................27
第三章 實驗步驟與研究方法.....................................29
3-1 儀器設備..................................................29
3-1-1 製程機台............................................29
3-1-2 量測機台............................................32
3-2 實驗步驟流程..............................................36
3-2-1 實驗流程............................................36
3-2-2 基板選擇............................................36
3-2-3 基板清洗............................................36
3-2-4 熱退火..............................................37
3-2-5 TEM準備流程........................................38
3-2-6 FTIR...............................................38
3-2-7 光致發光光譜儀......................................40
3-2-8 蒸鍍透明導電膜......................................40
3-2-9 熱處理..............................................40
3-2-10 背電極之選擇.......................................41
3-2-11 元件製作之流程.....................................44
第四章 結果與討論.............................................44
4-1不同退火溫度條件對於SiOx薄膜之量測結果與分析...............44
4-1-1 不同退火溫度之FTIR分析.............................44
4-1-2 SiOx薄膜退火後之TEM.................................46
4-2光致發光光譜儀分析.........................................46
4-2-1 不同退火溫度之光致發光光譜儀之分析...................46
4-2-2 不同SiOx薄膜厚度之光致發光光譜儀分析................52
4-3 透明導電膜氧化銦錫(ITO)之分析..............................56
4-3-1 熱處理前後的氧化銦錫之比較...........................56
4-3-2 不同熱處理溫度的氧化銦錫之穿透率比較.................60
4-3-3 不同熱處理持平時間的氧化銦錫之穿透率比較.............60
4-3-4 不同熱處理持平時間的氧化銦錫之霍爾量測...............63
4-4 元件之分析.................................................67
4-4-1 I-V曲線之探討.......................................67
4-4-2 電激發光光譜之量測...................................70
第五章 結論....................................................73
第六章 未來展望................................................74
第七章 參考文獻................................................75






目錄

圖2.1 奈米材料結構形式
圖2.2 自發輻射示意圖
圖2.3 LED發光示意圖
圖2.4 PL示意圖
圖2.5 EL示意圖
圖2.6 霍爾原理
圖2.7 分子振動方式示意圖
圖2.8 穿透式電子顯微鏡示意圖
圖2.9 XPS原理示意圖
圖2.10 布拉格方程式幾何關係圖
圖3.1 TEM試片前處理
圖3.2 元件製作流程
圖3.3 光照規格
圖4.1 SiO1.11薄膜退火之FTIR
圖4.2 SiOx薄膜厚度約為4000Å退火之1000℃之TEM圖
圖4.3 SiO1.11薄膜不同退火溫度之光致發光光譜圖
圖4.4 SiO1.11薄膜不同退火溫度之光致照片
圖4.5 SiO1.23薄膜不同退火溫度之光致發光光譜圖
圖4.6 SiO1.23薄膜不同退火溫度之光致照片
圖4.7 ITO薄膜熱處理後之照片
圖4.8 ITO薄膜熱處理後之XRD
圖4.9 ITO薄膜未經熱處理之XRD
圖4.10 ITO薄膜熱處理溫度400至550℃之穿透率
圖4.11 ITO薄膜熱處理溫度550至750℃之穿透率
圖4.12 ITO薄膜熱處理時間不同之穿透率
圖4.13 ITO薄膜經熱處理後與文獻比較圖
圖4.14 SiOx薄膜厚度約為560Å製成元件之I-V曲線
圖4.15 SiO1.15薄膜退火1000℃至成元件之EL光譜圖

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