고품질의 오프축을 가진 이종성장 다이아몬드 기판 위에 제작된 보론 도핑 다이아몬드 MOSFET = Boron doped Diamond MOSFET Fabricated on High Quality Off axis hetero-epitaxial diamond substrate

다국어 초록 (Multilingual Abstract)

Boron doped Diamond MOSFET Fabricated on High Quality Off axis hetero-epitaxial diamond substrate by Eonhee Roh Advisor : Prof. Nam Okhyun, Ph.D Department of Nano & Semiconductor Engineering Graduate School Tech University of Korea In this study, We report the first demonstration of a boron-doped diamond MOSFET fabricated on a hetero-epitaxial diamond substrate with a 7° off-axis angle. The device employs a UID-grown p⁻ channel and a selectively grown p⁺ contact layer, combined with a 30 nm Al₂O₃ gate insulator. This structure achieves a low on-resistance of 1.12 × 10³  Ω·cm² and stable gate control with low leakage current. C–V and I–V analyses confirmed reliable MOS behavior and effective carrier injection. Despite the high threading dislocation density associated with hetero-epitaxial growth, the device exhibited comparable breakdown characteristics to those on bulk substrates. This validates the feasibility of high-misorientation substrates for power electronics. The results highlight the potential of scalable diamond electronics for future high-voltage and high-temperature applications.

목차 (Table of Contents)

• ABSTRACT 9
• Chapter 1. Introduction 10
• 1.1 Research Background 10
• 1.1.1 The Role of Ultra-Wide Bandgap (UWBG) Semiconductors 10
• 1.1.2 Diamond: The Ultimate UWBG Semiconductor 13
• 1.1.3 Growth method of single crystal diamond 15
• 1.2 Feature of Hetero-epitaxial diamond substrate 18
• 1.2.1 defect density 20
• 1.2.2 Off-axis substrates for quality improvement 22
• 1.3 Recent status of Diamond device 25
• 1.4 Issues of boron-doped diamond FET 28
• 1.5 My approach 34
• 1.6 Experimental equipment 36
• 1.6.1 Microwave plasma chemical vapor deposition 36
• 1.6.2 Device fabrication equipment 37
• 1.6.3 Electronical characteristic measurement tools 39
• 1.7 Reference 42
• Chapter 2. Boron-doped diamond grown on off-axis hetero-epitaxial diamond substrate 45
• 2.1 Introduction 45
• 2.2 Homo-epitaxial diamond grown on misoriented angle hetero-epitaxial substrate 45
• 2.2.1 Experimental method 45
• 2.2.2 Homo-epitaxial diamond growth process 46
• 2.3 Characteristics of grown diamond on the misoriented homo-epitaxial diamond 49
• 2.3.1 Surface morphologies of diamond substrate and growth layer 49
• 2.4 Boron doped diamond grown on 7∘ off-axis hetero-epitaxial substrate 53
• 2.4.1 Experimental method 53
• 2.4.2 Growth & fabrication process 53
• 2.5 Characteristics of difference boron doped at 7∘ off-axis diamond 56
• 2.5.1 Surface morphologies of diamond substrate and growth layer 56
• 2.5.2 HT-Hall measurement characteristics of boron-doped diamond 60
• 2.6 Summary 65
• 2.7 Reference 67
• Chapter 3. Boron-doped diamond MOSFET fabricated on hetero-epitaxial diamond substrate 69
• 3.1 Introduction 69
• 3.2 Experimental method 71
• 3.2.1 Growth process of boron-doped MOSFET 71
• 3.2.2 Device fabrication process of boron-doped MOSFET 76
• 3.3 Characteristics of MOSFET on the homo-epitaxial diamond substrate 81
• 3.3.1 HT-Hall measurement characteristics of boron-doped diamond 81
• 3.3.2 I-V Curve depending on the transmission line model 84
• 3.3.3 I-V Characteristics of boron-doped MOSFET 88
• 3.3.4 C-V characteristics of boron-doped MOSFET 93
• 3.3.5 Breakdown voltage of boron-doped MOSFET 96
• 3.4 Benchmark for Ron and breakdown voltage characteristics 99
• 3.5 Summary 103
• 3.6 Reference 105
• CONCLUSION 109
• RESEARCH ACHIEVEMENTS 112
• ABSTRACT (KOREAN) 114