相對於已商業化以藍寶石基板為主的氮化鎵系列發光二極體，本論文旨在研發高效率之免切割垂直結構金屬基板之氮化鎵系列發光二極體(VM-LED)，結合球格陣列構裝(Ball Grid Array Package, BGA)及區塊雷射剝離(Patterned laser lift-off)技術置換藍寶石基板，以解決絕緣的藍寶石基板因散熱不佳、僅已橫向傳導所帶來電流叢聚效應(Current crowding effect)以及兩電極在同一面造成較小發光面積等問題，進而提升光輸出功率以及發光效率，並且克服了金屬基板切割時的剪應力及金屬噴濺所造成元件漏電問題。再者，為了提升區塊錫/銀/銅金屬基板上保留雷射剝離後磊晶的完整性，適度將元件剝離尺寸小於區塊錫/銀/銅金屬基板可大幅提升剝離後磊晶完整的良率，經實驗結果證實，VM-LED元件亦可得到相當於整面電鍍金屬基板之發光效率的增加。
另外，使用乾蝕刻(Dry-etching)-電感耦合電漿(ICP)與化學蝕刻(Chemical etching)-氫氧化鉀(KOH)溶液進行n-GaN表面處理之垂直元件製作，由實驗結果顯示，以24 mil元件來比較，在120 mA工作電流條件下，傳統橫向結構LED的Vf值為3.83V，Sn/Ag/Cu金屬基板垂直結構LED的Vf值為3.17 V，降低了0.66V。光輸出功率(ΔLOP / LOP)比傳統元件高出169%。而在電流20~120mA範圍間，串聯電阻值也降低了57%。

In this study, a dicing-free substrate technology using solder-balls with pattern laser lift-off technique to simplified both fabrication and packaging process for GaN-based LEDs is reported and demonstrated. In conjunction with keeping the size of epilayer smaller than that of Sn/Ag/Cu substrate, a considerable improvement in yield and device performance were shown. As compared to conventional GaN-based light-emitting diodes (LEDs) with sapphire substrate (abbreviated as regular LEDs), Vertical-structured metallic-substrate LEDs (abbreviated as VM-LEDs) show the superiority in better thermal conductivity , less current crowding effect, and 32% larger emission area than that of regular LEDs for a chip size of 600 μm.
To further improve the contact characteristics and light extraction of VM-LED, a surface treatment on n-GaN, employing dry-etching by inductive coupled plasma (ICP) and wet-etching by KOH solution, has also been made. As is evident from the experimental results, VM-LEDs with the proposed substrate technology was found to have a 57% lower serial resistance, a 0.66 V drop in forward voltage and an increase in light output power (Lop) by 169% at 120 mA compared with regular LEDs.

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