以氮化鎵為主體的藍色發光二極體是目前製作白光發光二極體的主要元件，而在能源日益缺乏的今天，以發光二極體來取代傳統的白熾燈光源是一個節能的有效選擇，是以如何成功的製備高功率，高穩定性和高效率的發光二極體元件顯得相當重要。 在本研究中，我們成功的利用金矽共熔鍵合和雷射舉離技術來製造薄氮化鎵發光二極體元件，薄氮化鎵結構已被證實具有高散熱性和高電流分佈性等優點，而我們更進一步證實了金矽共熔鍵結乃一可靠度高，熱穩定性佳的鍵合方法。足以適用製備薄氮化鎵發光二極體結構。由拉曼圖譜結果中可以發現氮化鎵薄膜在元件製備過程中釋放了其壓應力，並經由改變鍵合條件（金層厚度，鍵合溫度），我們可以控制這個壓應力釋放的值，經由實驗，最大的壓應力釋放值出現在金層厚度10 μm的時候，其值為290 MPa。而此製作完成的元件在工作電流為20 mA的情況下其正向偏壓和光強度資料分別為3.4 V和204 mcd。 本論文並深入探討在薄氮化鎵結構製備過程中氮化鎵薄膜應力的變化，隨著鍵合熱處理和雷射舉離製程，薄膜應力都會受到影響。而消除氮化鎵的薄膜應力將會有效地抑制氮化鎵發光層在磊晶時受到壓縮應力而導致能帶形變的問題，故藉由控制製程參數，我們可以成功地製備出效率較高的發光二極體元件。 Using Au-Si wafer bonding and LLO (Laser Lift-Off) techniques, an LED (Light Emitting Diode) GaN epi-layer was successfully transferred onto a Si substrate. After the wafer bonding, a KrF excimer laser was used to separate the GaN layer from the grown sapphire substrate. The Raman spectra results show that the initial compressive stress level of the GaN epi-layer was relieved after transferring. According to Kozawa’s relation, we got the relationship between the biaxial stress and various Au bonding layer thickness ranging from 7 μm to 40 μm. The maximum compressive stress relief, 290 MPa, in the transferred GaN thin film occurred at the largest Raman peak position shift of 10 μm Au layer (red shift, 1.79 cm-1). The transferred GaN epi-layer was further processed for use in a thin-GaN LED device. The L-I-V curve results indicate a forward voltage of 3.4 Volts, and a luminance intensity of 204 mcd at 20 mA. A detail stress evolution during thin-GaN LED fabrication was studied, and then the lighting intensity with different biaxial in-plane stress was also measured. We proved that we can avoid QCSE (Quantum Confined Stark Effect) efficiently by relieving the compressive stress. And the order of compressive stress relief can be controlled by changing the process parameters. The non-linear parabolic relation of the QW (Quantum Well) band gap with the stress level was also mentioned.
