次微米圖樣化藍寶石基板應用於氮化鎵發光二極體之研究

A Study of Submicron Patterned Sapphire Substrates Applied to GaN-based Light-Emitting Diode

洪献智(Hsien-Chih Hung)

指導教授 ： 李有璋

中原大學/工學院/機械工程研究所/碩士(2010年)

https://doi.org/10.6840/cycu201000944

摘要

本論文目的主要在於探討利用不同蝕刻擋層，完成次微米圖樣化藍寶石基板，並探究結構尺寸與圖樣種類，對於發光二極體的電特性和發光強度的影響。基板蝕刻擋層的製作，以奈米球微影及傳統微影方式，定義出圖形。首先，奈米球微影以旋塗方法將聚苯乙烯小球塗佈於藍寶石基板，作為基板的蝕刻擋層，而為了增加結構蝕刻深度，可將小球旋轉塗布於鍍上二氧化矽之藍寶石基板，二氧化矽作為第二層擋層，聚苯乙烯奈米小球尺寸分為300 nm、500 nm和800 nm。另外，傳統微影擋層製作方式則分為兩種：第一種方式，於基板上使用電漿輔助化學汽相沈積系統沈積厚度270 nm之二氧化矽，光阻塗布後經微影程序，而其中又以直接接觸方式，讓基板與光罩緊密貼合曝光，使得光罩圖形經由曝光、顯影後，能轉至第二層擋層的二氧化矽；第二種方式，先是利用上述接觸微影製程，做出圖形光阻，再於電子束蒸鍍系統中，鍍上鎳之厚度為250 nm，用光阻剝落法去除光阻完成蝕刻基板的鎳擋層。最後用濕式或乾式蝕刻法將上述使用奈米球微影與傳統微影方式所定義的基板，蝕刻出次微米等級的洞狀與柱狀圖樣化的藍寶石基板，並且討論微米與次微米圖樣化藍寶石基板在磊晶與晶粒製程之後，對電特性與光特性的影響。

關鍵字

發光二極體 ； 圖樣化藍寶石基板

並列摘要

The main purpose of this thesis is to use different etching mask to fabricate sub-micron patterned sapphire substrates (PSS), and analyze the influences of pattern type and size on the electric characteristic and light output power of light emitting diode. The patterns of etching mask were defined by the nanosphere lithography and conventional lithography respectively. For nanosphere lithography, polystyrene (PS) nanospheres were sprayed on the sapphire substrates by a spin coater. In order to increase the etching depth of sub-micron PSS, it may deposit a SiO2 layer as another mask layer between PS spheres and substrate first. In this study, nanospheres of polystyrene include the size of 300 nm, 500 nm and 800 nm. For conventional lithography, first was to deposit 270 nm thick SiO2 on the substrate by plasma-enhanced chemical vapor deposition (PECVD), then photoresist was spun on the SiO2. Contact printing was performed to enable the photo mask and photoresist contact without air gaps, and the mask pattern could be transferred to SiO2 after exposure and develop process. Secondly, using the same contact printing to define the photoresist pattern, and then deposit a 250 nm nickel layer by an E-gun evaporator. After the lift-off process, an etching mask of nickel was accomplished. Wet or dry etching was used to fabricate sub-micron hole and pillar sub-micron PSS via above nanosphere, SiO2 and nickel etching masks. Finally, epitaxy and chip process were performed to finish the LED process. The electrical and optical characteristics were measured to understand the influences of micron and sub-micron PSS.

並列關鍵字

LED ； PSS

參考文獻

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