GaN基LED是近年來被大量研究之題材，但其所採用藍寶石基板不導熱及不導電所衍生的種種問題卻無法有效解決。針對此點我們提出以鍍鎳金屬基板並配合雷射剝離技術（Laser lift-off）置換藍寶石基板，進行具垂直結構LED之研製，一舉解決傳統GaN基LED包括元件散熱不良、電流分佈不均、低流明通量與發光不均等諸多方面的問題。
　　
　　本論文使用原屬於機械精密加工所廣用的248 nm的KrF準分子雷射配合電鍍鎳金屬基板製程，不僅可迅速於數分鐘內移除2吋直徑藍寶石基板，成功將原成長於藍寶石上之氮化鎵薄膜置換至鍍鎳基板。據材料量測結果顯示，磊晶層並沒有因雷射加工而造成損害。
　　
　　於垂直結構LED之製程中，我們提出包括利用ICP乾蝕刻以增加試片p-GaN層表面濃度，降低元件順向偏壓與串聯電阻，以及浸泡KOH溶液濕蝕刻以在試片表面產生粗化效果，增加光輸出功率。實驗結果顯示，12 mil-LED元件順向偏壓比傳統元件降低0.1~0.2 V (@ 20 mA)，而串聯電阻更是減少約50％，於20 mA工作電流條件下的光輸出功率，最多可比傳統元件增加185％，在在顯示使用金屬基板垂直式元件之優勢，而所製得具垂直結構LED之光電特性遠較傳統橫向結構LED優異。
　　
　　本論文亦進行大面積(40 mil  40 mil)垂直結構LED之研製。量測所得光輸出功率於350 mA工作電流條件下，甚至可比傳統者增加226％，且其串聯電阻均較傳統平面式元件降低30％以上。於相同順向偏壓情況下，其power efficiency可由2.36％提升至7.68％，不僅可降低能源的耗損，元件於大電流、高功率之工作條件下，其可靠度也會大為提升。

　　In recent years, there have been many researches focusing on the GaN-based LED. However, a number of issues still persist when using sapphire as the substrate; they include the current crowding effect, the poor dissipation of heat, and low illumiance, etc. Incorporated with laser lift-off (LLO) technology to remove the sapphire substrate, a novel method using an electro-plating nickel substrate is proposed to realize high power GaN-based LEDs with a real vertical structure (VM-LED).
　　
　　In this thesis, the KrF excimer laser (wavelength = 248 nm) was used for the laser lift-off process. Technology to remove 2-inch sapphire within a few minutes was developed. Material characterization results reveal that the present LLO process does not infringe any damage to the epi-GaN layer.
　　
　　In experiments, surface treatment to the upmost GaN epilayer using inductive coupling plasma (ICP) dry etching and KOH wet etching together was proposed to further enhance the performance of vertical structure LEDs. For 12 mil VM-LEDs, it is found that the series resistance was reduced by 50% comparing to the conventional lateral type devices, and the forward voltage is also lowered by about 0.1~0.2 V (@ 20 mA). At a forward current of 20 mA, the light output power (LOP) of 12 mil VM-LEDs was enhanced by 185% as compared the conventional LEDs of the same chip size. For larger chip size devices (e. g. the 40-mil VM-LEDs), the measured power efficiency raised form 2.36％ to 7.68％ at a forward current of 350 mA, in addition, the best improvement in LOP as high as 226% was achieved. It is expected that the proposed fabrication method for the realization of vertical structure VM-LEDs would considerably improve both the power of efficiency and the power level for future lighting and high power applications.

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