利用濕式蝕刻製作圖樣化藍寶石基板於發光二極體之研究

A study on patterned sapphire substrates light-emitting diodes by using wet etching

李克濤(Ko-Tao Lee)

指導教授 ： 張正陽

國立中央大學/理學院/光電科學研究所/碩士(2007年)

摘要

本論文主要探討使用化學濕式蝕刻法來蝕刻藍寶石基板及其在雷射剝落法製作垂直式藍色發光二極體上之應用。化學濕式蝕刻其優點在於製程快速、成本低廉、選擇性佳且蝕刻之晶面光滑。圖樣化藍寶石基板可以降低氮化鎵磊晶層之錯位密度，提升磊晶品質，不同線寬之光柵式圖形對發光效率有不同之影響。圓洞狀圖樣化藍寶石基板可將發光二極體之電激發光強度提升2倍強。另外，使用晶片鍵合技術及雷射剝落法將氮化鎵磊晶層由散熱差的藍寶石基板移轉至散熱好的矽基板上製作之垂直式藍色發光二極體，並藉由在單一雷射脈衝區域內不同位置之光激發光光譜品質改變，了解脈衝雷射轟擊對氮化鎵磊晶層之影響。最後我們結合濕式蝕刻、晶片鍵合及雷射剝落技術製作出高品質氮化鎵磊晶之垂直式發光二極體。此一製程可在雷射剝落製程後完成垂直式之出光側之光柵圖形轉印，直接製作出光表面處理，提升其光激發光強度達2.86倍。

關鍵字

圖樣化藍寶石基板 ； 發光二極體 ； 垂直式發光二極體 ； 雷射剝落法 ； 濕蝕刻

並列摘要

In this study, we prepared a patterned sapphire substrate by chemical wet etching for the fabrication of vertical type blue light-emitting diode by laser lift-off process. The advantages of chemical wet etching are fast process, low cost, good selectivity and smooth etching surface. The patterned sapphire substrate can decrease the dislocation density of GaN epilayer and improve the luminous efficacy, which is also a function of the line-width of stripe grating patterns. The intensity of electroluminescence of the circular patterned sapphire substrate light-emitting diode is 2 times large than the conventional LED. The wafer bonding and laser lift-off techniques were used to transfer GaN epilayer from sapphire substrate to silicon substrate to form the vertical type light-emitting diode. In addition, we investigated the impact of pulsed excimer laser epilayer by examining the photoluminescence spectra on different sites of GaN after the laser lift-off process. We will combine chemical wet etching, wafer bonding and laser lift-off techniques to fabricate the light-emitting diode with high quality GaN epilayers. Thd pattern can be transferred after laser lift-off process and increase the photoluminence intensity to 2.86 times large than conventional structures.

並列關鍵字

patterned sapphire substrate ； light-emitting diode ； vertical-type LED ； chemical wet etching ； laser lift-off

參考文獻

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