臺灣博碩士論文加值系統

在這篇論文中，我們選擇了兩種高介值材料作為金氧半電容器之閘極介電層。ㄧ個是鏑氧化物，另一個是鈥氧化物。透過熱退火處理，我們分析它的物理特性。我們利用X射線繞射、X射線電子能譜儀和原子力顯微鏡來鑑定氧化層結晶體、化學組成成分和表面形態。接著我們用鋁當作閘極電極之後，探討其電性及可靠度。電性分析有C-V曲線圖、遲滯現象、介面態位密度和漏電流。我們發現鏑氧化物及鈥氧化物在熱退火600℃下有較大的電容值和較低的遲滯電壓，而且我們也探討鏑氧化物和鈥氧化物的可靠度。在鏑氧化物當中，我們探討閘極氧化物可靠度當中的崩潰電荷及依時介電層崩潰，在崩潰電荷，其韋伯斜率幾乎是和電流密度、面積及溫度無關;在依時介電層崩潰，其韋伯斜率幾乎是和電壓大小無關。在鈥氧化物當中，我們探討閘極氧化物可靠度當中的崩潰電荷，其中韋伯斜率幾乎是和電流密度、面積及溫度無關。我們發現這兩種高介電質材料的氧化層崩潰屬於本質崩潰。其意味著氧化層崩潰是由應力誘發電荷捕捉所造成的。最後，利用細胞基礎模型可求得鏑氧化物的缺陷尺寸。鏑氧化物的缺陷大小對α = 0.6為4.5 nm和對α = 1為7.5 nm

In this thesis, we selected two high-k materials as the gate dielectric of metal-oxide-semiconductor capacitors. One is dysprosium oxide (Dy2O3) and the other is holmium oxide (Ho2O3). Through PDA treatment, we analyzed its physical properties. We use X-ray diffraction (XRD), X-ray photoelectron Spectroscopy (XPS), and Atomic Force Microscopy (AFM) to identify the oxide film crystallization, chemical composition, and surface morphology. After using Al as gate electrode, we investigated its electrical and reliability characteristics. The analyses of electrical properties have C-V curves, hysteresis phenomenon, interface state density, and leakage current. We found dysprosium oxide and holmium oxide have a larger capacitance value when the annealing temperature is 600℃ and exhibited a lower hysteresis voltage. And, we also explored the reliability of dysprosium oxide and holmium oxide. In dysprosium oxide, we discuss charge-to-breakdown (QBD) and time-dependent-dielectric-breakdown (TDDB) in gate oxide reliability. The Weibull slope is almost independent of current stress, gate area, and temperature for Dy2O3 in QBD. The Weibull slope is almost independent of stress voltage for Dy2O3 in TDDB. In holmium oxide, we discuss charge-to-breakdown (QBD) in gate oxide reliability. The Weibull slope is almost independent of current stress, gate area, and temperature for Ho2O3 in QBD. We found the oxide breakdown for these two high-k material belonged to intrinsic breakdown. It means the oxide breakdown is caused by stress-induced charge traps. Finally, we used the cell-base analytic model to extract the defect size of Dy2O3 thin film. The defect size of Dy2O3 is 4.5 nm for α=0.6 and 7.5 nm for α=1.

Contents
誌謝 i
摘要 ii
ABSTRACT iv
Contents vi
Table Captions ix
Figure Captions x
Chapter 1 Introduction 1
1-1 Background 1
1-2 The application of high-k thin films 2
1-3 Motivation 3
1-4 Organization of the Thesis 3
Chapter 2 Thermodynamic Stability 7
2-1 The Introduction of thermodynamic stability 7
2-1 Other related literatures 8
Chapter 3 The Physical Properties of Al/Dy2O3/p-type Si (100) MOSCAPs 11
3-1 Introduction 11
3-2 Experiment 11
3-3 Result and Discussion 12
3-3-1 X-ray diffraction (XRD) of dysprosium oxide film analyses 12
3-3-2 X-ray photoelectron spectroscopy (XPS) of dysprosium oxide film analysis 13
3-3-3 Atomic Force Microscopy (AFM) of dysprosium oxide film analysis 14
Chapter 4 The Electrical Properties of Al/Dy2O3/p-type Si (100) MOSCAPs 21
4-1 Capacitor characteristics of Dy2O3 gate dielectric 21
4-2 Hysteresis phenomenon characteristics of Dy2O3 gate dielectric 22
4-3 Interface state density characteristics of Dy2O3 gate dielectric 23
4-4 J-V characteristics of Dy2O3 gate dielectric 24
4-5 The Reliability characteristics of Dy2O3 gate dielectric 24
4-5-1 The discussion of gate oxide breakdown 24
4-5-2 Lifetime distribution model 25
4-5-3 The relationship between  and current density 27
4-5-4 The relationship between  and gate area 27
4-5-5 The relationship between  and temperature 28
4-6 Summary 28
Chapter 5 The Electrical Properties of Al/Dy2O3/p-type Si (100) MOSCAPs 45
5-1 Capacitor characteristics of Dy2O3 gate dielectric 45
5-2 Hysteresis phenomenon characteristics of Dy2O3 gate dielectric 45
5-3 Interface state density characteristics of Dy2O3 gate dielectric 45
5-4 I-V and J-E characteristics of Dy2O3 gate dielectric 46
5-5 The Reliability characteristics Dy2O3 gate dielectric 46
5-5-1 The relationship between  and gate area 46
5-5-2 The concept of defect size in the percolation model 46
5-5-3 The analysis of Time Dependent Dielectric Breakdown (TDDB) 48
Chapter 6 The Physical Properties of Al/Ho2O3/p-type Si (100) MOSCAPs 61
6-1 Introduction 61
6-2 Experiment 61
6-3 Result and Discussion 62
6-3-1 X-ray diffraction (XRD) of holmium oxide film analyses 62
6-3-2 X-ray photoelectron spectroscopy (XPS) of holmium oxide film analysis 63
6-3-3 Atomic Force Microscopy (AFM) of holmium oxide film analysis 64
Chapter 7 The Electrical Properties of Al/Ho2O3/p-type Si (100) MOSCAPs 71
7-1 Capacitor characteristics of Ho2O3 gate dielectric 71
7-2 Hysteresis phenomenon characteristics of Ho2O3 gate dielectric 72
7-3 Interface state density characteristics of Ho2O3 gate dielectric 73
7-4 J-V characteristics of Ho2O3 gate dielectric 74
7-5 The Reliability characteristics of Ho2O3 gate dielectric 74
7-5-1 The discussion of gate oxide breakdown 74
7-5-2 Lifetime distribution model 75
7-5-3 The relationship between  and current density 76
7-5-4 The relationship between  and gate area 77
7-5-5 The relationship between  and temperature 77
7-6 Summary 78
Chapter 8 Conclusions and Future Work 95
8-1 Conclusions 95
8-2 Future Work 95
References 96

Table Captions
Chapter 1
Table 1-1 Printed gate length (nm) and equivalent oxide thickness (EOT) for high performance (hp) MOSFET according to the 2008 ITRS roadmap. 5
Table 1- 2 Comparison of relevant properties of high-k materials. 6
Chapter 3
Table 3-1 The process flow of MOS capacitor with Dy2O3 gate dielectric 15
Chapter 4
Table 4-1 The CET, the relative permittivity (εr), the hysteresis, and the interface state density (Dit) of Dy2O3 MOSCAP are calculated for as-dep and different annealing temperature. 29
Chapter 5
Table 5-1 Comparison of the defect sizes of Dy2O3 film and of conventional SiO2. 51
Chapter 6
Table 6-1 The process flow of MOS capacitor with Ho2O3 gate dielectric 65
Chapter 7
Table 7- 1 The CET, the relative permittivity (εr), the hysteresis, and the interface state density (Dit) of Ho2O3 MOSCAP are calculated for as-dep and different annealing temperature. 79

Figure Captions
Chapter 2
Fig. 2- 1 The three types of M-Si-O phase diagrams : (a) metal oxide dominate (b) no phase dominate (c) SiO2 dominate. A reaction flowchart showing what two reactions can be used to identify which type a particular M-Si-O system belongs if the system contains no ternary phases (MSixOy) and only one Mx phase [8]. 9
Fig. 2-2 Summary of which elements M have (a) a metal oxide (MOx) and (b) a metal nitride (MNx) that may be thermodynamically stable in contact with silicon at 1000 K [8]. 10
Chapter 3
Fig. 3-1 The process flow for the fabrication of MOS capacitor with Dy2O3 gate dielectric. 17
Fig. 3-2 XRD of Dy2O3 film for as-deposited and annealed at different temperatures in O2 ambient for 30s. 17
Fig. 3-3 XPS results of (a) O 1s and (b) Dy 4d5/2 in Dy2O3 thin film after annealing at different temperature for Ar:O2 = 20:10. 18
Fig. 3-4 AFM image of Dy2O3 film without PDA. 19
Fig. 3-5 AFM image of Dy2O3 film with PDA 600℃. 19
Fig. 3-6 AFM image of Dy2O3 film with PDA 700℃. 20
Fig. 3-7 AFM image of Dy2O3 film with PDA 800℃. 20
Chapter 4
Fig. 4-1 The C-V curves of Dy2O3 MOS capacitor for gas flow ratio Ar:O2 = 20:10 with different temperatures in O2 ambient for 30s. 30
Fig. 4-2 Capacitance equivalent thickness (CET) values of the Dy2O3 film for as-deposited and different temperature. 30
Fig. 4-3 Hysteresis voltage of Dy2O3 gate dielectric versus different annealing temperature for Ar:O2 = 20:10. 31
Fig. 4-4 The G-V curve of Dy2O3 gate dielectric before and after post-annealing for Ar:O2 = 20:10. 31
Fig. 4-5 Interface trap density (Dit) of Dy2O3 gate dielectric before and after post-annealing for Ar:O2 = 20:10. 32
Fig. 4-6 Gate current density as a function of gate voltage of Dy2O3 gate dielectric for Ar:O2 = 20:10 before and after PDA treatment. 32
Fig. 4-7 V-t curves for Dy2O3 capacitor with oxide thickness 12 nm. 33
Fig. 4-8 V-t curves for Dy2O3 capacitor with oxide thickness 12 nm. 33
Fig. 4-9 V-t curves for Dy2O3 capacitor with oxide thickness 12 nm. 34
Fig. 4-10 QBD distributions for Dy2O3 capacitor with oxide thickness 34
Fig. 4-11 QBD distributions for Dy2O3 capacitor with oxide thickness 35
Fig. 4-12 QBD distributions for Dy2O3 capacitor with oxide thickness 35
Fig. 4-13 QBD distributions for Dy2O3 capacitor with oxide thickness 36
Fig. 4-14 V-t curves for Dy2O3 capacitor with gate area=3.14×10-4 cm2. The stress current density was Jstress=0.16 mA/cm2. 36
Fig. 4-15 V-t curves for Dy2O3 capacitor with gate area=1.26×10-3 cm2. The stress current density was Jstress=0.16 mA/cm2. 37
Fig. 4- 16 V-t curves for Dy2O3 capacitor with gate area=5.02×10-3 cm2. The stress current density was Jstress=0.16 mA/cm2. 37
Fig. 4-17 QBD distributions for Dy2O3 with gate area=3.14×10-4 cm2. 38
Fig. 4-18 QBD distributions for Dy2O3 with gate area=1.26×10-3 cm2. 38
Fig. 4-19 QBD distributions for Dy2O3 with gate area=5.02×10-3 cm2. 39
Fig. 4-20 QBD distributions for Dy2O3 with gate area=3.14×10-4, 1.26×10-3, and 5.02×10-3 cm2. The stress current density was Jstress=0.16 mA/cm2. 39
Fig. 4-21 Area dependence of 63% QBD value. The stress current density was Jstress=0.16 mA/cm2. 40
Fig. 4-22 V-t curves for Dy2O3 capacitor at T=300k. The stress current density was Jstress=0.16 mA/cm2. 40
Fig. 4-23 V-t curves for Dy2O3 capacitor at T=350k. The stress current density was Jstress=0.16 mA/cm2. 41
Fig. 4-24 V-t curves for Dy2O3 capacitor at T=400k. The stress current density was Jstress=0.16 mA/cm2. 41
Fig. 4-25 QBD distributions for Dy2O3 at T=300k. The stress current density was Jstress=0.16 mA/cm2. 42
Fig. 4-26 QBD distributions for Dy2O3 at T=350k. The stress current density was Jstress=0.16 mA/cm2. 42
Fig. 4-27 QBD distributions for Dy2O3 at T=400k. The stress current density was Jstress=0.16 mA/cm2. 43
Fig. 4-28 QBD distributions for Dy2O3 at T=300, 350, and 400k. The stress current density was Jstress=0.16 mA/cm2. 43
Fig. 4-29 The Arrhenius plot of Dy2O3 thin film. The Ea was 2.21 eV 44
Chapter 5
Fig. 5-1 High frequency (1 MHz) C-V characteristics of Dy2O3 thin film capacitor measures from -5V to 2V. 52
Fig. 5-2 Hysteresis of Dy2O3 gate dielectric measures from -5V to 2V and sweep back. 52
Fig. 5-3 Interface state density versus energy trap level. 53
Fig. 5-4 I-V characteristic of Dy2O3 thin film capacitor is under negative bias. 53
Fig. 5-5 J-E characteristic of Dy2O3 thin film capacitor is under negative bias. 54
Fig. 5-6 QBD distributions for Dy2O3 with gate area=3.14×10-4, 1.26×10-3, and 2.83×10-3 cm2. Ramp rate was 1 MV/cm‧sec. 54
Fig. 5-7 Area dependence of 63% QBD value.The ramp rate was 1 MV/cm‧sec. 55
Fig. 5-8 Weibull slope versus physical oxide thickness compared to [16]. 55
Fig. 5-9 I-t curves for Dy2O3 capacitor under CVS= -7V with oxide thickness 15 nm. 56
Fig. 5-10 I-t curves for Dy2O3 capacitor under CVS= -7.5V with oxide thickness 15 nm. 56
Fig. 5-11 I-t curves for Dy2O3 capacitor under CVS= -8V with oxide thickness 15 nm. 57
Fig. 5-12 tBD distributions for Dy2O3 under CVS= -7V with oxide thickness 15 nm. 57
Fig. 5-13 tBD distributions for Dy2O3 under CVS= -7.5V with oxide thickness 15 nm. 58
Fig. 5-14 tBD distributions for Dy2O3 under CVS= -8V with oxide thickness 15 nm. 58
Fig. 5-15 tBD distributions for Dy2O3 under three different voltage with oxide thickness 15 nm. 59
Fig. 5-16 The lifetime extrapolation for Dy2O3 thin film capacitors at 25℃. For E model. 59
Fig. 5-17 The lifetime extrapolation for Dy2O3 thin film capacitors at 25℃. For 1/E model. 60
Chapter 6
Fig. 6- 1 The process flow for the fabrication of MOS capacitor 67
Fig. 6-2 XRD of Ho2O3 film for as-deposited and annealed at different temperatures in O2 ambient for 30s. 67
Fig. 6-3 XPS results of (a) O 1s and (b) Ho 4d in Ho2O3 thin film after annealing at various temperatures for Ar:O2 = 20:10. 68
Fig. 6-4 AFM image of Ho2O3 film without PDA. 69
Fig. 6-5 AFM image of Ho2O3 film with PDA 600℃. 69
Fig. 6-6 AFM image of Ho2O3 film with PDA 700℃. 70
Fig. 6-7 AFM image of Ho2O3 film with PDA 800℃. 70
Chapter 7
Fig. 7-1 The C-V curves of Ho2O3 MOS capacitor for gas flow ratio Ar:O2 = 20:10 with different temperatures in O2 ambient for 30s. 80
Fig. 7-2 The capacitance equivalent thickness (CET) values of the Ho2O3 film for as-deposited and different temperature. 80
Fig. 7-3 Hysteresis voltage of Ho2O3 gate dielectric versus different annealing temperature for Ar:O2 = 20:10. 81
Fig. 7-4 The G-V curve of Ho2O3 gate dielectric before and after post-annealing for Ar:O2 = 20:10. 81
Fig. 7-5 Interface trap density (Dit) of Ho2O3 gate dielectric before and after post-annealing for Ar:O2 = 20:10. 82
Fig. 7-6 Gate current density as a function of gate voltage of Ho2O3 gate dielectric for Ar:O2 = 20:10 before and after PDA treatment. 82
Fig. 7-7 V-t curves for Ho2O3 capacitor with oxide thickness 11nm. 83
Fig. 7-8 V-t curves for Ho2O3 capacitor with oxide thickness 11nm. 83
Fig. 7-9 V-t curves for Ho2O3 capacitor with oxide thickness 11nm. 84
Fig. 7-10 QBD distributions for Ho2O3 with oxide thickness 11nm. 84
Fig. 7-11 QBD distributions for Ho2O3 with oxide thickness 11nm. 85
Fig. 7-12 QBD distributions for Ho2O3 with oxide thickness 11nm. 85
Fig. 7-13 QBD distributions for Ho2O3 with oxide thickness 11nm. 86
Fig. 7-14 V-t curves for Ho2O3 capacitor with gate area=3.14×10-4 cm2. The stress current density was Jstress=0.32 mA/cm2. 86
Fig. 7-15 V-t curves for Ho2O3 capacitor with gate area=1.26×10-3 cm2. The stress current density was Jstress=0.32 mA/cm2. 87
Fig. 7-16 V-t curves for Ho2O3 capacitor with gate area=5.02×10-3 cm2. The stress current density was Jstress=0.32 mA/cm2. 87
Fig. 7-17 QBD distributions for Ho2O3 with gate area=3.14×10-4 cm2. 88
Fig. 7-18 QBD distributions for Ho2O3 with gate area=1.26×10-3 cm2. 88
Fig. 7-19 QBD distributions for Ho2O3 with gate area=5.02×10-3 cm2. 89
Fig. 7-20 QBD distributions for Ho2O3 with gate area=3.14×10-4, 1.26×10-3, and 5.02×10-3 cm2. The stress current density was 0.32 mA/cm2. 89
Fig. 7-21 Area dependence of 63% QBD value. The stress current was Jstress=0.32 mA/cm2. 90
Fig. 7-22 V-t curves for Ho2O3 capacitor at T=300k. The stress current density was Jstress=0.32 mA/cm2. 90
Fig. 7-23 V-t curves for Ho2O3 capacitor at T=350k. The stress current density was Jstress=0.32 mA/cm2. 91
Fig. 7-24 V-t curves for Ho2O3 capacitor at T=400k. The stress current density was Jstress=0.32 mA/cm2. 91
Fig. 7-25 QBD distributions for Ho2O3 at T=300k. The stress current density was Jstress=0.32 mA/cm2. 92
Fig. 7-26 QBD distributions for Ho2O3 at T=350k. The stress current density was Jstress=0.32 mA/cm2. 92
Fig. 7-27 QBD distributions for Ho2O3 at T=400k. The stress current density was Jstress=0.32 mA/cm2. 93
Fig. 7-28 QBD distributions for Ho2O3 at T=300, 350, and 400k. The stress current density was Jstress=0.32 mA/cm2. 93
Fig. 7-29 The Arrhenius plot of Ho2O3 thin film. The Ea was 3.9 eV. 94

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