Title Page
Abstract
Contents
List of Abbreviations 19
1. Introduction 22
1.1. Study Background 22
1.2. Purpose of Research 23
1.3. Bibliography 27
2. Switching Mechanism in Semiconductor-based Ferroelectric Capacitor 29
2.1. Introduction 29
2.2. Experimental 31
2.3. Results and Discussions 33
2.4. Conclusion 48
2.5. Bibliography 49
3. Analysis on Memory Window in MFMIS and MFIS Ferroelectric Capacitor 51
3.1. Introduction 51
3.2. Experimental 53
3.3. Results and Discussions 59
3.4. Conclusion 80
3.5. Bibliography 81
4. Decomposition of Interface Layer by Oxygen-Scavenging Effect 83
4.1. Introduction 83
4.2. Experimental 89
4.3. Results and Discussions 91
4.4. Conclusion 114
4.5. Bibliography 115
5. Conclusion 119
Curriculum Vitae 121
List of Publications 125
Abstract in Korean 136
Table 2-1. Coercive voltages and applied voltage distribution at 10 nm- and 20 nm-thick HZO ferrolectric layers when the thickness of interface... 39
Figure 2-1. Schematic and fabrication process of HZO-based MFS capacitor. 32
Figure 2-2. Polarization hysteresis of MFS capacitors (highly-doped p-type Si) with (a) 10 nm-, (b) 20 nm-, and (c) 30 nm-HZO films. Current-... 34
Figure 2-3. (a) SEM images of 10 nm-, 20 nm, and 30 nm-HZO films for average grain size measurement. (b) GIXRD measurements of 10... 36
Figure 2-4. (a) Light depletion operation in MFS capacitor with highly-doped Si substrate. Sufficient negative space charges formed by... 41
Figure 2-5. (a) Polarization hysteresis of 20 nm-HZO MFIS capacitors with interface SiO₂ layers at thickness of 2 nm, 0.7 nm, and removed... 43
Figure 2-6. (a) Deep depletion operation in MFS capacitor with lightly-doped Si substrate. Insufficient negative space charges formed by... 45
Figure 2-7. (a) Polarization characteristics of 20 nm-HZO MFS capacitor with lightly-doped Si substrate. No ferroelectric switching occurs at... 47
Figure 3-1. Configuration of serially-connected metal-ferroelectric-metal (MFM) and metal-insulator-semiconductor (MIS) capacitors to... 54
Figure 3-2. MFMIS structures with different areas of HZO-based MFM stack and MIS stacks of (a) Al₂O₃ on lightly-doped n-type Si substrate... 56
Figure 3-3. (a) Flat-band and (b) inversion / accumulation conditions of Al₂O₃ - based MIS capacitor when static dipoles are formed at the... 57
Figure 3-4. Fabrication flow and top-view of the fabricated ring-type ferroelectric metal-oxide-capacitor (FeMOSCAP) 58
Figure 3-5. (a) Capacitance characteristics of MIS capacitor with no inversion (deep depletion) operation. (b) Voltage distribution at each... 60
Figure 3-6. (a) Double-ramp pulse (positive first) applied to MFM+MIS configuration. (b) Ferroelectric switching-induced hysteresis of... 61
Figure 3-7. (a) Polarization hysteresis of HZO-based MFM stack in MFMIS structure. (b) Capacitance hysteresis of MIS (Al₂O₃ on n-type Si)... 63
Figure 3-8. (a) Capacitance hysteresis of HZO-based MFMIS structure with MIS (Al₂O₃ on n-type Si) area ratio of (a) 4, (b) 16, and (c) 36.... 64
Figure 3-9. (a) Polarization hysteresis of HZO-based MFM stack in MFMIS structure. (b) Capacitance hysteresis of MIS (SiO₂ on p-type Si)... 66
Figure 3-10. (a) Capacitance hysteresis of HZO-based MFMIS structure with MIS (SiO₂ on p-type Si) area ratio of (a) 4, (b) 16, and (c) 36. Trap-... 67
Figure 3-11. (a) Positive-up-negative-down (PUND) pulse with intermediate delays for back-switching of switched polarization. Positive uni-... 68
Figure 3-12. Capacitance characteristics of as-deposited MIS capacitors with (a) 4 nm- and (b) 5.5 nm-Al₂O₃ on lightly-doped n-type Si... 70
Figure 3-13. Schematics of HZO- and HZAHZ-based MFIS capacitors with (a) 5 nm-Al₂O₃ on n-type Si and (b) 5 nm-SiO₂ on p-type Si substrate.... 71
Figure 3-14. Switching and non-switching polarization behavior of (a) HZO- and (b) HZAHZ-based MFIS (n-type) capacitors measured by... 72
Figure 3-15. Schematics of (a) 12 nm- and (b) 22 nm-HAO MFIS capacitors with 5 nm-Al₂O₃ on n-type Si substrate. (c) Polarization hysteresis... 74
Figure 3-16. Switching and non-switching polarization behavior of (a) 12 nm- and (b) 22 nm-HAO MFIS (n-type) capacitors measured by PUND... 75
Figure 3-17. Schematics of (a) 17 nm- and (b) 25 nm-HAO MFIS capacitors with 1.5 nm-Al₂O₃ on n-type Si substrate. (c) Polarization... 77
Figure 3-18. Switching and non-switching polarization behavior of (a) 17 nm- and (b) 25 nm-HAO MFIS (n-type) capacitors measured by PUND... 78
Figure 3-19. (a) Capacitance characteristics of fabricated ring-type nMOSCAP with inversion operation. (b) Switching-induced capacitance... 79
Figure 4-1. Schematics of 10 nm-Al-doped HfO₂ (HAO) MFIS capacitors with (a) 50 nm-TiN and (b) 50 nm-TiN/5 nm-Ti/5 nm-TiN top electrodes. 87
Figure 4-2. Polarization-voltage (P-V) characteristics of 800 ℃-annealed HAO-based MFIS capacitors with TiN and TiN/Ti/TiN top... 88
Figure 4-3. Grazing incidence x-ray diffraction (GIXRD) patterns of (a) PDA, (b) TiN PMA and (c) TiN/Ti/TiN PMA conditions at 600-800℃... 93
Figure 4-4. Phase transitions of non-polar monoclinic m(111) phase and polar orthorhombic o(111) phase for TiN PMA condition with the... 94
Figure 4-5. Capacitance-voltage (C-V) characteristics of (a) 600℃, (b) 700℃ and (c) 800℃-annealed HAO-based MFIS (lightly-doped Si)... 97
Figure 4-6. Cross-sectional high-resolution transmission electron microscope (HRTEM) images of 800 ℃-annealed 10 nm-HAO-based MFIS... 100
Figure 4-7. Energy-dispersive X-ray spectroscopy (EDS) mapping images of Hf, O, Si, N, and Ti elemental compositions for (a) TiN/HAO/Si... 102
Figure 4-8. Frequency dispersions of capacitance characteristics measured at a frequency range from 1 kHz to 100 kHz for (a) 600 ℃, (b) 700 ℃,... 105
Figure 4-9. (a) Capacitance-voltage (C-V) characteristics and (b) frequency dispersions of 800 ℃-annealed HAO-based MFIS (heavily-doped... 108
Figure 4-10. (a) Schematic of TiN/Ti/TiN MFIS structure showing the overall mechanism of the oxygen-scavenging process. (b) Polarization-... 113