本論文以電漿輔助式分子束磊晶法，在藍寶石基板上成長氧化銦鎵錫薄膜以作為透明導電膜的應用。首先成長氧化銦鎵薄膜(In1-xGaxO，x表示鎵在化合物中的原子百分比)，利用不同鎵的蒸氣分子通量控制氧化銦鎵薄膜中鎵的濃度。藉由X射線繞射譜分析、穿透光譜以及霍爾效應分析薄膜的光電特性。結果發現當鎵原子濃度(x)在0.41以下時，薄膜呈獻立方晶型的氧化銦鎵；當0.41<x<0.7時，則呈現非晶結構；進一步提高x至0.7以上，則再次呈現為晶體結構（單斜體的氧化銦鎵）。然而，氧化銦鎵的光穿透率最高達86%，導電率卻僅有3.4×10-2 ohm-cm，此特性無法達到市面上對透明導電膜的需求。因此，選擇最佳的氧化銦鎵薄膜成長條件，加入錫以成長一系列氧化銦鎵錫薄膜。從X射線繞射譜分析發現錫原子百分濃度低於70%時，薄膜皆呈現非晶結構，此時的電阻率可達到4.0×10-4 ohm-cm，而且光穿透可達94%以上。而且，其表面粗糙度僅有1.5 nm。最後，我們發現調變基板成長溫度有改善電性，從600 oC降至400 oC導電率提升了1.5倍。

In this work, InGaSnO (IGTO) thin films were grown by plasma-assisted molecular beam epitaxy in order to demonstrate quaternary semiconductor IGTO suitable for transparent conductive oxide (TCO) applications. First of all, In1-xGaxO (x means the cation atoms percentage of the gallium in the compound) thin films were fabricated on sapphire. Concentration of material Ga was controlled by tuning Ga cell temperature between 480 oC ~700 oC, and value of x was between 0.34 ~ 0.7, respectively. The X-ray diffraction (XRD), Transmittance, and Hall measurement are employed to characterize the physical and electrical properties. When x is lower than 0.41, IGO thin films are revealed cubic structure. However, IGO thin films are appeared amorphous between 0.41< x <0.7. With flux of Ga rising above 0.7, crystalline of monoclinic structure of IGO is exhibited by XRD results. Furthermore, high transmittance is estimated as 86% and resistivity is 3.4×10-2 ohm-cm. For TCO requirement, the results of IGO thin films are insufficient on its electrical characterization. In the second step, Sn was lead into IGO to produce high electrical efficiency quaternary semiconductor IGTO. XRD results were demonstrated amorphous structure of IGTO thin films which exhibited lowest resistivity as 4.0×10-4 ohm-cm and high transmittance 94% approximately when concentration of Sn was smaller than 70%. In further, surface roughness was calculated only 1.5 nm by atomic force microscope (AFM). Finally, reducing growth temperature was obtained the best electrical efficiency behavior, conductivity is increase 1.5 times from 600 oC to 400 oC.

致謝 I
摘要 II
Abstract III
目錄 V
List of Figures and Tables VII
Chapter 1. Introduction 1
Chapter 2. Experiment 4
2.1 Crystal structure of In2O3, Ga2O3and SnO2 4
2.2 Homemade molecular beam epitaxy system 9
2.3 Optical spectroscopy 11
2.4 Sample preparation 17
2.5 Sample growth parameters 17
2.5.1 Samples growth via In2O3 base with Ga flux 17
2.5.2 Samples growth via InGaO base with Sn flux 18
2.5.3 Samples growth via InGaSnO change temperature of substrate 19
Chapter 3. Results and discussion 23
3.1 Characterization of InGaO thin films 23
3.2 Characterization of InGaSnO thin film 32
3.3 Influence of growth temperature (Tsub) and substrate type in InGaSnO 39
Chapter 4. Conclusion 44
References 45

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