隨著固態照明的需求日益上升，高功率垂直結構GaN-基LED吸引了相當的注意。主因其n-GaN向上之垂直結構，提供了較傳統p-GaN向上水平導通之GaN-基LED為佳的電流擴展能力，提升光析出效果。本質上，n-GaN之擴散長度約在120~130 m之譜；以300x300 m2之元件面積為例，其電流擴展能力無法完整涵蓋整體元件。同時，為提升每晶粒流明通量，大電流操作為元件發展之趨勢。此一電流擴展不均的狀況，致使元件在大電流操作之下，平均單位光電轉換效率下降。
本論文旨在利用具微米陣列之垂直結構GaN基LED(μ-LED)改善此一情況。微米陣列發光二極體係利用感應耦合電漿系統將元件蝕刻至微米尺寸之陣列。整以IZO透明導電薄膜、SiO2鈍化保護層之使用，將微米陣列相連接成一個網絡並大幅度提升電流擴展均勻度於每一單位面積。於實驗之初，使用ISE模擬軟體進行元件電性模擬分析，由模擬結果可看出，微米陣列結構比起標準整面結構(broad-area)，其電流的分布更均勻。實驗結果顯示，在順向電流為100 mA時，與broad-area GaN-基LED相較，μ-LEDs每一單位面積之光輸出功率改善幅度達140% (broad-area LED和μ-LED的總發光面積為9×104 µm2和2.25×104 µm2)。我們更進一步將元件驅動至700 mA，μ-LEDs之光輸出仍維持相當的穩定而無明顯光功率飽和之發生。相較之下，broad-area之元件於390 mA發生飽和。此一結果明顯揭示所提之結構有效將電流擴展均勻度提升，改善元件光電轉換效率，減緩熱效應之影響。值得注意的是，於0~700 mA，每單位面積之光電轉換效率皆優於標準整面結構。

Vertical structure GaN-based light-emitting diodes (VM-LEDs) have attracted much attention. This is because its n-side up structure design with metallic substrates enables much better current spreading, light extraction efficiency, and thermal dissipation capability as compared with conventional lateral conducting sapphire substrate GaN-based LEDs.
Essentially, current spreading length provided by n-GaN is around 120 µm. This is sufficient for those devices with chip sizes under 300x300 µm2. However, as the chip size goes up for the pursuit of increment in luminous flux per chip, one chip could not be effectively fully covered. The light extraction efficiency per unit area lowered, power conversion efficiency decreases, and device performance corrupts under high injection current eventually. Use of electrode geometry design, transparent conductive layers (TCL), and surface engineering have been sequentially proposed and reported with stimulating results.
In this thesis, we managed to release the situation by implementing micro-array structures on standard VM-LEDs (broad-area LEDs). 2x2 and 8x8 micro-array VM-LEDs(µ-LEDs) were fabricated. Based on the experimental results, 102% and 140% improvements over broad-area LEDs in the normalized light output power (Lop) at 100 mA were observed on 2x2 and 8x8 µ-LEDs, respectively. The improvement increased with the array number, because the proposed µ-LED enable better and effective current spreading per unit area and reflected in the normalized Lop. Together with the comparable current-voltage (I-V) characteristics, the power conversion efficiency per area of 2x2 and 8x8 µ-LEDs was 91.6% and 116% superior.
We further boost the 8x8 µ-LEDs and broad-area LEDs up to 700 mA for Lop-I measurement (not normalized) to examine stability of both device performance under high injection current. One saw that the Lop broad-area LEDs dropped at 390 mA. In the contrast, the Lop of µ-LEDs remained steady response throughout the testing region, and led that of broad-area LEDs at 410 mA.

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