대표어
학술연구정보서비스(KERIS)
권호기사보기
| 기사명 | 저자명 | 페이지 | 원문 | 기사목차 |
|---|
국회도서관 홈으로
정보검색
소장정보 검색
결과 내 검색
동의어 포함
-
-
목차보기
Title Page
ABSTRACT
Contents
CHAPTER 1. Introduction 15
1.1. Background and Motivation 15
1.2. Thesis Organization 17
CHAPTER 2. Schottky Barrier Height Engineering for n-type Ge 18
2.1. MIS Contact Technique 18
2.1.1. Concepts of MIS Contact Technique 18
2.1.2. MIS Contact Modeling with MIGS Theory 22
2.1.3. MIS Contact with Ultrathin Interlayers 25
2.2. Surface Passivation Technique 28
2.2.1. SF6 Plasma Treatment Technique(이미지참조) 28
2.2.2. H₂ and N₂ Thermal Annealing Technique 35
2.3. Summary 37
CHAPTER 3. Optimization of MIS Contact for n-type Ge 38
3.1. Interlayer Engineering 38
3.1.1. Ar Plasma Treatment Technique 38
3.1.2. Post-Deposition H₂ Thermal Annealing Technique 42
3.1.3. Heavily Doped Interlayer Insertion 48
3.1.4. Effect of Interlayer Resistance in Heavily Doped Ge 49
3.2. Interface Engineering 52
3.2.1. Post-Deposition H₂ and N₂ Thermal Annealing Technique 52
3.2.2. Plasma Oxidation Technique 54
3.3. Thermally Stable MIS Contact Structure 66
3.3.1. Selection of Contact Metal 67
3.3.2. Selection of Interlayer 76
3.4. Summary 86
CHAPTER 4. Comprehensive Analysis of Schottky Barrier Height Modulation 88
4.1. Interface Dipole Formation 88
4.2. Distinction between Fermi-Level Unpinning and Interface Dipole 92
4.3. Contact Surface Orientation Dependency 97
4.4. Summary 102
CHAPTER 5. Schottky Barrier Height Engineering for MoS₂ 103
5.1. Motivation of Schottky Barrier Height Engineering for MoS₂ 103
5.2. Fermi-Level Pinning in MoS₂ 104
5.3. Schottky Barrier Height Engineering for Electrical Contacts of MoS₂ 108
5.4. MoS₂ p-FETs Using Schottky Barrier Height Modulation 120
5.5. Summary 122
CHAPTER 6. Conclusions 124
REFERENCES 126
국문초록(Abstract in Korean) 133
CURRICULUM VITAE 134
Figure 1.1. (From [2]) Channel and parasitic resistances in planar CMOS technology for technology nodes. 15
Figure 1.2. (a) Specific contact resistivity vs. semiconductor doping concentration plot (log-log) for SBH of... 17
Figure 2.1. Schematic energy band diagrams of (a) MS and (b) MIS structures showing blocking of electron... 18
Figure 2.2. (From [4]) SBH on n-Si and n-Ge for various metal contacts. 19
Figure 2.3. Energy band diagrams of (a) MS and (b) MIS contact structures adopting contact metal with low... 20
Figure 2.4. (a) electron SBH and (b) specific contact resistivity of MIS contact structures adopting low-work-... 21
Figure 2.5. (a) Calculated electron SBH of MIS contact structures for n-Ge as a function of the TiO₂ interlayer... 24
Figure 2.6. (a) J-V characteristics of Ti/n-Ge and Ti/TiO₂/n-Ge contact structures for different TiO₂ thickness.... 26
Figure 2.7. Energy band diagrams of (a) Ti/n-Ge, and (b, c) Ti/TiO₂/n-Ge contact structures with (b) thinner... 26
Figure 2.8. Energy band diagrams of (a) Ti/TiO₂/n-Ge and (b) Ti/Y₂O₃/n-Ge contact structures. 27
Figure 2.9. J-V characteristics of Ti/n-Ge and Ti/Y₂O₃/n-Ge contact structures for different Y₂O₃ thickness, (b)... 27
Figure 2.10. J-V characteristics of (a) Ti/n-Ge and (b) Ti/p-Ge contact structures with different SF6 plasma...(이미지참조) 29
Figure 2.11. Energy band diagrams of Ti/n-Ge contact structures (a) without and (b) with SF6 plasma treatment,...(이미지참조) 30
Figure 2.12. (a) Back-to-back current density at a bias voltage of 0.1 V and (b) specific contact resistivity of... 31
Figure 2.13. XPS spectra of SF6 plasma-treated Ge surface for different treatment time durations for (a) F 1s,...(이미지참조) 32
Figure 2.14. Surface images of Ge surface which is treated by SF6 plasma for (a) 0 sec, (b) 30 sec, and (c) 60...(이미지참조) 33
Figure 2.15. Electron SBH of Ti/n-Ge contact structures for different SF6 plasma treatment time durations.(이미지참조) 34
Figure 2.16. Calculated pc values as a function of Ge doping concentrations for 0 sec and 30 sec of SF6 plasma...(이미지참조) 34
Figure 2.17. J-V characteristics of Ti/n-Ge contact structures with and without H₂ thermal annealing and N₂... 35
Figure 2.18. Ge 3d XPS spectra of n-Ge substrates without thermal annealing (bare Ge) and with H₂ thermal... 36
Figure 3.1. Back-to-back J-V characteristics of Ti/n-Ge and Ti/TiO₂ (1 ㎚)/n-Ge with and without At plasma... 39
Figure 3.2. O Is XPS spectra of (a) as-deposited 3-㎚-thick TiO₂ layer and (b) Ar plasma-treated (for 40 sec)... 40
Figure 3.3. Relative specific contact resistivity of Ti/TiO₂ (1 ㎚)/n-Ge contact structures with and without Ar... 41
Figure 3.4. Energy band diagrams of (a) Ti/TiO₂/n-Ge and (b) Ti/TiO2-x/n-Ge contact structures showing...(이미지참조) 41
Figure 3.5. Calculated ρc as a function of Ge doping concentration obtained from TCAD simulation with...(이미지참조) 42
Figure 3.6. J-V characteristics of Ti/n-Ge, Ti/TiO₂ (1 ㎚)/n-Ge with and without the PDHA at 400 ℃ for 30... 43
Figure 3.7. JR at V ＝ -0.5 V of Ti/TiO2-x (1 ㎚)/n-Ge contact structures with the PDHA for different annealing...(이미지참조) 44
Figure 3.8. JR of Ti/TiO₂ (1 ㎚)/n-Ge contact structures with and without the PDHA for different TiO₂...(이미지참조) 45
Figure 3.9. Ti 2p spectra of TiO₂/n-Ge structure with and without the PDHA at 400 ℃ for 30 min. (b)... 46
Figure 3.10. Specific contact resistivity of Ti/n-Ge and Ti/TiO2-x/n-Ge with the PDHA for different Ge doping...(이미지참조) 47
Figure 3.11. Corrected total resistance vs. gap spacing in C-TLM measurement of the Ti/TiO2-x/n+-Ge contact...(이미지참조) 47
Figure 3.12. A brief description of the C-TLM measurement. 48
Figure 3.13. Specific contact resistivity of Ti/n+-Ge, Ti/TiO2-x/n+-Ge with the PDHA, and Ti/AZO/n+-Ge with...(이미지참조) 49
Figure 3.14. Specific contact resistivity on n+-Ge (left) and JR at V＝-0.5 V on n-Ge (right) of four different...(이미지참조) 50
Figure 3.15. Energy band diagrams of (a) Ti/n-Ge, (b) Ti/TiO₂/n-Ge, (c) Ti/n+-Ge, and (d) Ti/TiO₂/n+-Ge...(이미지참조) 51
Figure 3.16. Energy band diagrams of the MIS contact structures with (a) interlayer doping technique and (b)... 52
Figure 3.17. Ge 3d spectra of TiO₂/n-Ge structure, with and without the PDHA at 400 ℃ with 100 SCCM H₂... 53
Figure 3.18. Ge 3d spectra of TiO₂/n-Ge structure, with and without the post-deposition H₂ or N₂ thermal... 54
Figure 3.19. J-V characteristics of (a) Ti/n-Ge, Ti/TiO₂ (1 ㎚)/n-Ge, and Ti/TiO₂ (1 ㎚)/GeO₂ (1.5 ㎚)/n-Ge... 56
Figure 3.20. J-V characteristics of Ti/TiO₂/GeO₂/n-Ge contact structure for three different GeO₂ thickness with... 57
Figure 3.21. Ge 3d XPS spectra of (a) bare n-Ge, (b) TiO₂/n-Ge, (c) TiO₂/GeO₂/n-Ge with 30 sec of plasma... 58
Figure 3.22. JR at a bias voltage of -0.7 V of (a) Ti/TiO₂ (1 ㎚)/GeO₂/n-Ge structures created by different...(이미지참조) 59
Figure 3.23. J-V characteristics of Ti/TiO₂ (1 ㎚)/GeO₂/n-Ge structures for 30 sec and 70 sec of plasma... 60
Figure 3.24. Oxide thicknesses formed by different plasma oxidation time durations, (inset) Cross-sectional... 60
Figure 3.25. J-V characteristics of Ti/n-Ge, Ti/TiO₂ (1 ㎚)/n-Ge, and Ti/TiO₂ (1 ㎚)/post-GeOx (30 sec)/n-Ge....(이미지참조) 61
Figure 3.26. Ge 3d XPS spectra of TiO₂/post-GeOx (30 sec)/n-Ge.(이미지참조) 61
Figure 3.27. Ti 2p XPS spectra of TiO₂/n-Ge and TiO₂/post-GeOx (30 sec)/n-Ge stacks(이미지참조) 62
Figure 3.28. J-V characteristics of Ti/p-Ge and Ti/TiO₂ (1 ㎚)/GeO₂ (1.5 ㎚)/p-Ge structures where the... 63
Figure 3.29. Energy band diagrams of (a) Ti/p-Ge structure and (b) Ti/TiO₂ (1 ㎚)/GeO₂ (1.5 ㎚)/p-Ge... 64
Figure 3.30. Corrected RT for C-TLM spacing in the C-TLM measurement of Ti/TiO₂ (1 ㎚)/GeO₂ (1.5 ㎚)/n-...(이미지참조) 65
Figure 3.31. Spreading resistance profiles (SRP) of Ge n+/p junction formed with two conditions(이미지참조) 65
Figure 3.32. Box plots of JR values of Ti/n-Ge and Ti/TiO₂/n-Ge contact structures with different TiO₂...(이미지참조) 68
Figure 3.33. J-V characteristics of Ti/n-Ge and Ti/TiO₂ (1 ㎚)/n-Ge structures without thermal annealing and... 69
Figure 3.34. J-V characteristics of (a) Ti/n-Ge, (b) Ti/TiO₂ (1 ㎚)/n-Ge, (c) Ti/TiO₂ (2 ㎚)/n-Ge, and (d)... 70
Figure 3.35. TEM images of A1 electrode/Ti/TiO₂ (1 ㎚)/n-Ge structure (a) without thermal annealing and (b)... 71
Figure 3.36. Box plots of JR values of TaN/n-Ge and TaN/TiO₂/n-Ge structures with different TiO₂ thicknesses...(이미지참조) 73
Figure 3.37. J-V characteristics of TaN/TiO₂ (3 ㎚)/n-Ge structure without thermal annealing and after... 73
Figure 3.38. Film resistivity of Al (50 ㎚)/TaN (5 ㎚) film for various thermal annealing conditions. 74
Figure 3.39. (a), (b) TEM images of Al electrode/TaN/TiO₂ (1 ㎚)/n-Ge structure after thermal annealing at... 75
Figure 3.40. XRD patterns of 50-㎚-thick TiO₂ layer with different thermal annealing conditions: 'A' means... 75
Figure 3.41. Box plots of JR values of TaN/n-Ge and TaN/AZO/n-Ge structures with different AZO thicknesses...(이미지참조) 77
Figure 3.42. J-V characteristics of TaN/n-Ge structure without thermal annealing, TaN/n-Ge structure after... 78
Figure 3.43. N 1s XPS spectra obtained from the TaN/n-Ge structure (a) without thermal annealing and (b)... 78
Figure 3.44. TEM images of A1 electrode/TaN/n-Ge structure (a) after thermal annealing at 500 ℃ and (b)... 79
Figure 3,45. TEM images of (a), (b) Al electrode/TaN/AZO (2.8 ㎚)/n-Ge structure after thermal annealing at... 80
Figure 3.46. Average JR values of Ti/TiO₂/n-Ge structures with various interlayer thicknesses and thermal...(이미지참조) 81
Figure 3.47. Average JR values of TaN/TiO₂/n-Ge structures with various interlayer thicknesses and thermal...(이미지참조) 82
Figure 3.48. Average JR values of TaN/AZO/n-Ge structures with various interlayer thicknesses and thermal...(이미지참조) 82
Figure 3.49. Standard deviations (s) of log(JR) of (a) Ti/n-Ge and Ti/TiO₂/n-Ge, (b) TaN/n-Ge and TaN/TiO₂/n-...(이미지참조) 83
Figure 4.1. Mechanism of the FLP for (a) smaller-work-function contact metal and (b) larger-work-function... 88
Figure 4.2. (From [76]) Mechanism of the FLP for (a) smaller-work-function contact metal and (b) larger-... 89
Figure 4.3. (From [19]) Energy band diagrams of (a) Ti/TiO₂/GaAs and (b) Ti/ZnO/TiO₂/GaAs contact... 89
Figure 4.4. Oxygen areal density of four kinds of germanium oxides normalized to that of the TiO₂. 91
Figure 4.5. Schematic diagrams showing the oxygen diffusion and the interface dipole formation for (a) the... 91
Figure 4.6. J-V characteristics of (a) MS contact structures and (b) MIS contact structures with a 1-㎚-thick... 93
Figure 4.7. Richardson plots of (a) Ag/(110) n-Ge and (c) Ag/TiO₂ (1 ㎚)/(110) n-Ge contact structures for... 94
Figure 4.8. Electron SBH of MS and MIS structures with a 1-㎚-thick TiO₂ interlayer on (100) Ge substrates... 95
Figure 4.9. (a) Band alignment of the MIS contact structure showing the formation of interface dipoles at the... 96
Figure 4.10. Electron SBH of MS structures, MIS structures, and MIS structures without considering dipole... 97
Figure 4.11. Cross-sectional TEM images of (a) metal/TiO₂ (1 ㎚)/(100) n-Ge and (b) metal/TiO₂ (1 ㎚)/(110)... 98
Figure 4.12. J-V characteristics of (a) MS contact structures and (b) MIS contact structures with a 1-㎚-thick... 99
Figure 4.13. (a) Electron SBH of MS and MIS structures with a 1-㎚-thick TiO₂ interlayer on (110) Ge... 99
Figure 4.14. Ge 3d XPS spectra obtained from (a) bare (100) and (110) Ge substrates and (b) TiO₂ (1 ㎚)/(100)... 100
Figure 4.15. Calculated electron SBH of MIS contact structures on (100) and (110) Ge substrates with different... 101
Figure 5.1. (a) Process flow of multilayered MoS₂ FETs with both MS and MIS S/D contacts on the same... 104
Figure 5.2. (a) 3-D schematic illustration, (b) cross-sectional schematic, and (c) top-view optical microscopy... 105
Figure 5.3. 3-D schematic illustrations of back-gated multilayered MoS₂ FETs with (a) combined contacted... 106
Figure 5.4. Transfer characteristics (ID-VBG) of back-gated multilayered MoS₂ FETs with four metal contacts....(이미지참조) 107
Figure 5.5. Transfer characteristics (ID-VBG) of back-gated multilayered MoS₂ FETs with both MS and MIS...(이미지참조) 109
Figure 5.6. ID-VBG characteristics of multilayered MoS₂ FETs with MS S/D structures for (a) Ti, (c) Cu, (e) Au,...(이미지참조) 110
Figure 5.7. Back-to-back diode I-V characteristics of MS structures (metal-MoS₂-metal) and MIS structures... 111
Figure 5.8. Effective electron SBH of MS S/D contacts for (a) Ti, (c) Cu, (e) Au, and (g) Pt metal contacts, and... 113
Figure 5.9. (a) Arrhenius plots of MS S/D contacts for (a) Ti, (c) Cu, (e) Au, and (g) Pt metal contacts, and... 114
Figure 5.10. (a) Box plot of ID at VDS ＝ 0.5 V and zero back-gate bias of multilayered MoS₂ FETs with MS and...(이미지참조) 115
Figure 5.11. (a) Fitted lines of effective electron SBH under the flat-band bias condition of MS and MIS S/D... 116
Figure 5.12. (a) Cross-sectional schematic of multilayered MoS₂ FETs with the TiO₂ layer as the gate... 117
Figure 5.13. (a) Cross-sectional schematic of multilayered MoS₂ FETs with the TiO₂ layer deposited on top of... 118
Figure 5.14. (a) Transfer characteristics of multilayered MoS₂ FETs with Pt S/D contact for different TiO₂... 120
Figure 5.15. (From [113]) Band energies in flat-band condition of n-type materials with respect to Cu₂O and... 120
Figure 5.16. Energy band diagrams of (a) Pt/MoS₂ and (b) Pt/Cu₂O/MoS₂ contact structures. 121
Figure 5.17. Transfer characteristics of multilayered MoS₂ FETs with Pt contact and 30-㎚-thick Cu₂O... 122
Figure 6.1. Specific contact resistivity values of developed non-alloyed contact structures for n-Ge in... 125
초록보기
최신의 반도체 CMOS 기술에서 트랜지스터 소자의 소형화에 따라 소자의 크기가 나노미터 수준으로 줄어들면서 트랜지스터의 소스/드레인 컨택 저항이 소자의 동작전류 개선에 큰 걸림돌로 작용하고 있다. 때문에 CMOS 기술의 지속적인 발전을 위해서는 반도체 소자의 컨택 저항 감소에 대한 연구가 필수적이다. 기존 기술에서는 실리사이드 (silicide) 와 같은 합금형 (alloyed) 컨택을 통해 소자의 컨택 저항을 개선해왔으나, 이는 최신의 finFET 소자에 적용하기에는 여러가지 문제점을 지닌다. 그러므로 비합금형(non-alloyed) 컨택 기술이 차세대 CMOS 기술을 위해 개발되어야 한다. 비합금형 컨택 기술의 개발을 위해서는 반도체의 전기적 컨택의 쇼트키 장벽(Schottky barrier height)을 낮추는 것이 필수적인데, 많은 반도체 물질에서 페르미 레벨 피닝(Fermi-level pinning)이라는 현상으로 인해 반도체 컨택의 쇼트키 장벽을 조절하는 것이 쉽지 않다. 즉, 비합금형 컨택 기술의 개발을 위해서는 반도체의 전기적 컨택의 쇼트키 장벽을 조절하는 기술의 개발이 선행되어야 한다.
본 논문에서는 차세대 반도체 나노소자를 위해 매우 유망한 두 반도체 물질인 저마늄(germanium)과 MoS₂(molybdenum disulfide)의 전기적 컨택에서 쇼트키 장벽을 효과적으로 조절하기 위해 개발된 다양한 기술들을 소개하고자 한다. 페르미 레벨 피닝 현상의 완화와 계면 전기 쌍극자(interface dipole)의 형성을 통해 조절 가능한 쇼트키 장벽의 범위가 큰 폭으로 증가하였고, 페르미 레벨 피닝 현상의 완화를 위해 수 나노미터 수준의 중간층 삽입 및 계면 처리 공정을 개발하였다. 저마늄의 경우 컨택 저항 개선을 위한 전자 쇼트키 장벽의 감소와 비합금형 컨택 구조의 최적화 연구를 중점적으로 수행하였고, MoS₂ 의 경우 MoS₂ 기반 반도체 소자의 다양한 응용을 위해 쇼트키 장벽의 조절 기술을 개발하였다. 'MARC 보기
오류 데이터 정정요청
*표시는 필수 입력사항입니다.
알림톡 발송
| 전화번호 |
|---|
개인정보 수정 바로가기
연속간행물 권호 선택
우편복사 안내
- ◾ 도서관을 방문하지 못할 경우 인터넷, 팩스 등으로 자료 복사를 신청하고, 복사물을 우편·팩스 등으로 제공받는 서비스
- ◾ 대상자료: 일반도서, 연속간행물 및 학위논문
- ※ 고서, 고잡지, 훼손될 우려가 있는 자료, 마이크로폼 자료 및 신문 등 제외
- ◾ 신청 책수: 1인 5책 이하(1일 기준)
- ◾ 신청 절차: 자료 검색 → 우편복사 목록담기 → 복사 범위 입력 → 우편복사 주문서 입력 → 접수 및 확인
- ※ 저작권법에 의거하여 부분 복사(전체 페이지 수의 1/3 범위 이내)만 가능
- ◾ 복사 범위 입력 예시: (연속 페이지) 1-30, (부분 페이지) 25, 30-40
| 번호 | 발행일자 | 권호명 | 제본정보 | 자료실 | 원문 | 신청 페이지 |
|---|
도서위치안내(서울관)
도서위치안내: / 서가번호:
0
확인
우편복사 목록담기를 완료하였습니다.
내서재에 담기
새로운 서재
*표시는 필수 입력사항입니다.
저장
저장 되었습니다.