금속-산화물 반도체-금속 다이오드의 Cole-cole 분석에 관한 연구

다국어 초록 (Multilingual Abstract)

Recently, oxide semiconductors have been widely studied due to their high electron mobility, transparency, and good stability under bias stress. Many TFTs and diodes use oxide semiconductors as the active layer for these reasons. However, underlying physics of oxide semiconductor must be studied to widen our understanding of dynamics of electron transfer in the active layer and the interface. Among the various measurement methods, impedance spectroscopy is versatile. It has been used to analyze the electrochemical processes and structures of organic light-emitting diodes, lithium-ion batteries, and compound solar cells. In this thesis, Cole-cole analysis of metal-oxide semiconductor-metal diode was conducted to discover the electrical process under varying frequency. In chapter 2, the fabrication of the metal-oxide semiconductor-metal diode and measurement methods were explained. In chapter 3, atomic force microscopy (AFM) analysis of the metal- oxide semiconductor-metal diode was performed. Roughness and thickness of the a-IGZO layer were measured for each molar concentration. In chapter 4, Cole-cole analysis of the metal-oxide semiconductor-metal diode was conducted. To generate Cole-cole plots, capacitance-voltage measurements were performed under varying frequency. In chapter 5, Equivalent circuit modeling of the metal-oxide semiconductor-metal diode was induced using electrochemical impedance spectroscopy (EIS) simulation tool. The anodization of metal, tunneling effects, and schottky barrier exist for the equivalent circuits.

목차 (Table of Contents)

• Chapter 1 Introduction 1
• 1.1 Oxide Semiconductor 2
• 1.2 Amorphous InGaZnO 4
• 1.3 Impedance Spectroscopy 6
• 1.4 Metal-Semiconductor-Metal diode 9
• Chapter 2 Experimental 11
• 2.1 Diode fabrication 12
• 2.2 Measurements set up 14
• 2.3 Atomic force microscopy analysis 16
• Chapter 3 Cole-cole Measurements and Analysis 20
• 3.1 Capacitance-Voltage measurement 21
• 3.2 Frequency sweep analysis 23
• 3.3 Cole-Cole plot 25
• Chapter 4 Equivalent Circuits Modeling 30
• 4.1 Diode modeling and simulation 31
• 4.2 Anodization 35
• 4.3 Tunneling 37
• 4.4 Schottky barrier 39
• 4.5 Native oxide 41
• Chapter 5 Conclusion 43
• References 45