本論文主旨在進行具鍍鎳基板垂直結構氮化鎵蕭基二極體之研製。我們採用雷射剝離技術(Laser Lift Off, LLO)分離技術和電鍍鎳金屬以進行基板轉置的工作。

實驗結果歸納所得雷射剝離時的最佳加工條件是能量密度為850mJ/cm2 (對於1.70 A、5.20 V、溫度55oC，定電流鍍鎳90分鐘的條件下)。實驗中係以Ti/Al/Ti/Au製作n型GaN之歐姆接觸，經詳細分析退火條件對其接觸電阻值的影響，結果顯示Ti/Al/Ti/Au系統具有優良的熱穩定性和特徵接觸電阻值6.644×10-5 cm2。LLO製程後以AFM觀察undoped-GaN薄膜，其RMS值為4.598 nm。蕭基接觸研究方面，修正型Norde method萃取參數被用以評估不同的ICP及KOH表面處理條件下，對所製得的蕭基二極體電特性的影響，最後再以掃描式電子顯微鏡觀測其表面型態的改變。

In this thesis, the fabrication of GaN vertical Schottky Barrier diodes (SBDs) with Ni pseudo-substrate is studied. Laser Lift Off and Ni electroplating were employed for the removal of the GaN epilayers from the sapphire substrate and serving as a mechanical support for the huge strain in the epilayer as well as conducting substrate, respectively, for the realization of vertical-structure GaN SBDs.
The optimal laser energy to separate GaN epi layer and sapphire substrate is found to be of 850 mJ/cm2 with the nickel substrate was electroplated under the condition of 1.70A、5.20V at 55oC. Ti/Al/Ti/Au metal system was used as ohmic metal to the heavily doped n-type GaN. The influence of annealing condition on the Specific Contact Resistance (SCR) of the (Au/Ti/Al/Ti)/n-GaN contact system is also investigated. Experimental results reveal that the (Au/Ti/Al/Ti)/n-GaN contact system has a good thermal stability and a SCR value as low as 6.644×10-5 cm2. After laser lift off, surface quality of undoped GaN films was also observed by Atom Force Microscope (AFM) and Secondary Emission Microscopy (SEM) technology. Root-mean-square of surface roughness of 4.598 nm was obtained. Electronic characteristics of Schottky barrier diodes (SBDs) were also studied under different ICP and KOH surface treatment conditions.

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