提升UVC-LED 之發光強度方法主要有改善磊晶品質，包含p-GaN層之接觸電極改善，但改善p-GaN之磊晶有其困難度，提升成效有限。因此本實驗決定從藍寶石基板端做處理，利用陽極氧化鋁蝕刻遮罩，再以ICP蝕刻將AAO遮罩之凹槽型奈米圖案轉移至藍寶石基板上，以提升UVC-LED之光萃取效率，並提升整體發光強度。製程中藉由調整陽極氧化條件，包含酸液濃度、電極工作距離、擴孔時間，製備大尺寸之奈米圖案遮罩，並藉由ICP-RIE製程將凹槽圖案轉移到藍寶石基板上。
在基板前處理中，蒸鍍鋁膜的品質將會影響後續陽極氧化反應之成功與否，因此鍍鈦鋁之機台轉換時需要確保將樣品連續抽真空。在製程後半段利用ICP機台製備NPSS基板，但LED pad面有相變化的情況，可能原因為藍寶石基板散熱差、破片黏貼於矽基板，容易有熱效應之問題，使最後製程溫度>270℃。LED pad相變化將導致正向電壓上升、功率下降之問題。不過在最後UVC-LED之光學量測上，亮度仍有提升最高20% ，若未來改善LED pad相變化問題，可望大幅提升UVC-LED發光強度。

The primary methods for improving the emission intensity of UVC-LEDs involve enhancing the epitaxial quality, particularly focusing on improvements in the p-GaN layer and its contact electrodes. However, achieving significant enhancements through p-GaN epitaxy improvements presents challenges and limited effectiveness. Consequently, this experiment aims to address the issue from the substrate side.
The approach involves utilizing an anodic aluminum oxide (AAO) etching mask, which is subsequently transferred onto a sapphire substrate using inductively coupled plasma (ICP) etching. This process aims to enhance the light extraction efficiency of UVC-LEDs and elevate overall luminous intensity. During fabrication, adjustments are made to the anodization conditions, including acid concentration electrode working distance, and enlarging time to create large-sized nano pattern masks. The ICP-RIE process is then employed to transfer the pattern onto the sapphire substrate.
In the initial substrate preparation, the quality of the aluminum film deposited by thermal evaporation significantly impacts the success of subsequent AAO formation. Therefore, during the transition between titanium and aluminum deposition, ensuring continuous vacuum pumping of the samples is crucial. In the latter stages of the process, NPSS (nano-patterned sapphire substrate) is prepared using an ICP machine. However, there are observed phase changes on the LED pad surface, possibly due to differences in sapphire substrate heat dissipation or silicon wafer fragments adhering to the surface, leading to thermal effects. As a result, the final process temperature exceeds 270°C. These LED pad phase changes result in increased forward voltage and decreased power output. Nevertheless, in the final electrical measurements of UVC-LEDs, brightness still exhibits a maximum improvement of 20% . Addressing the LED pad variation issue in the future holds the potential for significantly enhancing UVC-LED luminous intensity.

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