二茂鎂流量對P型氮化鎵之結構、光性與電性影響

Influence of Cp2Mg flow rate on the structural,electrical,and optical properties of p-type GaN

顏穗安(Sui-An Yen)

指導教授 ： 周武清

國立交通大學/理學院/電子物理系所/碩士(2019年)

摘要

本論文利用金屬有機化學氣相沈積系統，透過調變二茂鎂流量，在矽(111)基板上成長正型氮化鎵，並透過光性、結構、電性三方面探究其表現及成長機制。
樣品主要發光機制為施子與授子對復合發光，隨二茂鎂流量提高，薄膜的發光機制會從導帶至授子或施子與授子對復合發光逐漸變成深施子與授子對復合發光，造成紅移現象。拉曼光譜顯示樣品主要受壓縮應力，並隨著流量上升往舒張應力方向偏移。
另外，發現隨著流量上升，其表面平整度下降，退火後表面亦不均勻，由能量擴散光譜確認為鎂原子摻入造成。並且量測X光繞射搖擺曲線計算其差排密度，和流量大致呈現正相關。
最後以霍爾量測得出其電洞濃度隨流量上升，最高達1.485x1018cm-3，並且以二次離子質譜儀量測鎂原子摻雜濃度得知活化率達2.06%，其與應力、差排密度變化及活化能下降有關。

關鍵字

鎂 ； 氮化鎵 ； 摻雜 ； 光性 ； 結構 ； 電性

並列摘要

In this thesis, the metal organic chemical vapor deposition system (MOCVD) is used to grow P-type gallium nitride on the Si (111) substrate by modulating the flow of Cp2Mg. Investigate its optical, structural, and electrical properties to explore the performance and growth mechanisms.
The dominant emission in the photoluminescence (PL) spectra is attributed to the donor-acceptor pair (DAP) recombination. As the flow rate of Cp2Mg increases, the luminescence mechanism of the sample will gradually change from conduction band to acceptor (eA) emission or DAP to deep donor-acceptor pair (DDAP) recombination, which results in a red shift in the emission energy. Raman spectroscopy indicates that the sample is mainly subjected to a compressive stress and shifts toward to the tensile stress as the flow rate increases.
In terms of structure investigation,the surface roughness increases with the increasing flow rate.The surface after annealing is also non-uniform, which is confirmed by energy dispersive spectroscopy (EDS) as the incorporation of magnesium atoms. The X-ray diffraction (XRD) rocking curve is measured to calculate the dislocation density, which is roughly positively correlated with the flow rate.
In terms of electrical properties, Hall measurement shows that the hole concentration increases with the flow rate up to 1.485×1018 cm-3.The Mg doping concentration was measured by the secondary ion spectrometry(SIMS) to calculate the hole activation rate as high as 2.06%, which might be due to the change in stress, dislocation density and the decrease in activation energy.

並列關鍵字

Mg ； GaN ； doped ； optical properties ； structural properties ； electrical properties

參考文獻

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