산화층을 높인 VCSEL의 설계 및 특성 분석
Design and Characterization of Elevated-Oxide VCSEL
- 주제(키워드) vcsel , semiconductor laser , reliability , secondary pulsation
- 발행기관 아주대학교
- 지도교수 SANG-BAE KIM
- 발행년도 2010
- 학위수여년월 2010. 8
- 학위명 박사
- 학과 및 전공 일반대학원 전자공학과
- 실제URI http://www.dcollection.net/handler/ajou/000000010867
- 본문언어 영어
- 저작권 아주대학교 논문은 저작권에 의해 보호받습니다.
초록/요약
Elevated-oxide VCSELs of which spacing between the 1-lambda cavity and oxide layer is greater than the conventional ones are designed, fabricated and characterized in order to achieve wide single-mode operation, stable turn-off performance, superior electro-static discharge (ESD) resistivity and reliability. Elevated-oxide VCSELs… structures are optimized using one-dimensional transfer matrix method combined with three-dimensional electro-thermal model, and compared with measured results. Also, the structure parameters such as metal and oxide aperture radii are optimized. Temperature dependent static and dynamic characteristics the elevated-oxide VCSELs are competent compared with conventional oxide VCSELs in terms of single-mode performance, turn-off characteristics and resistivity to ESD exposure. The single-mode operation range of the elevated-oxide-layer VCSELs is wider due to the smaller current confinement and optical confinement. The dynamic characteristics, particularly, turn-off characteristics of the elevated-oxide VCSELs are investigated. The turn-off-induced anomalies such as off-state turn-on and tails of the conventional and elevated-oxide VCSELs are extracted from the turn-off transient responses, and compared. Also, temperature dependence of the turn-off-induced anomalies is investigated. The optimum vertical position of the oxide layer and the oxide aperture diameter for high turn-off performance are proposed. With the optimum structure parameters, suppression of the turn-off-induced anomalies causing significant increases in timing jitter is achieved. Forward and reverse ESD-induced degradation behavior of the conventional oxide VCSELs is also investigated. Both the forward and reverse ESD-induced degradation incurred increase in the leakage current, threshold current and series resistance simultaneously with the decrease in the slope efficiency and effective active area. However, the reverse ESD causes more sudden and abrupt degradation than that of the forward ESD pulses due to the low reverse breakdown voltage. The structure dependent ESD damage threshold of four different types of elevated-oxide VCSELs shows that the elevated-oxide VCSELs are more robust to ESD damage than conventional oxide VCSELs due to reduced oxide-induced stress.
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TABLE OF CONTENTS
ABSTRACT i
ACKNOWLEDGEMENT iii
TABLE OF CONTENTS iv
LIST OF FIGURES ix
LIST OF TABLES xvi
CHAPTER I: INTRODUCTION 1
1.1. Recent advances in vertical-cavity surface-emitting lasers 1
1.2. Outline 5
1.3. Overview 6
CHAPTER II: DESIGN OF ELEVATED-OXIDE VCSELS 8
2.1. Introduction 8
2.2. Transfer matrix method 10
2.3. Design of conventional VCSELs 11
2.3.1. Position of the active layer 12
2.3.2. Optimization of the outermost layers 19
2.3.3. Distribution of the optical power 23
2.3.4. 1-D threshold current and slope efficiency 26
2.3.5. Interface-layer dependence of dynamic resistance 28
2.4. Design of elevated-oxide VCSELs 33
2.5. Fabrication of elevated-oxide VCSELs 35
2.6. Summary 36
CHAPTER III: STATIC CHARACTERISTICS OF
ELEVATED-OXIDE VCSELS 37
3.1. Introduction 37
3.2. Conventional VCSELs (Type CN) 39
3.2.1. Light output-current-voltage characteristics 39
3.2.2. Temperature dependence of L-I-V characteristics 40
3.2.3. Spectrum 42
3.3. 9lambda/4-elevated-oxide-layer VCSELs (Type EN) 45
3.3.1. Light output-current-voltage characteristics 45
3.3.2. Temperature dependence of L-I-V characteristics 45
3.3.3. Spectrum 47
3.4. 13lambda/4-elevated-oxide-layer VCSELs (Type E'N) 50
3.4.1. Light output-current-voltage characteristics 50
3.4.2. Temperature dependence of L-I-V characteristics 52
3.4.3. Spectrum 54
3.5. Temperature dependence of the single-mode operation range 56
3.5.1. Measured results 56
3.5.2. Discussion 61
3.6. Summary 71
CHAPTER IV: DYNAMIC CHARACTERISTICS OF
ELEVATED-OXIDE VCSELS 75
4.1. Introduction 75
4.2. Preparation for experiments 80
4.3. Turn-off transient responses 82
4.3.1. On-current dependence of turn-off transient responses 82
4.3.2. Off-current dependence of turn-off responses 88
4.4. Structure and temperature dependence of turn-off responses 91
4.4.1. Off-state turn-on 100
4.4.2. Slow tail 104
4.5. Eye-diagrams 107
4.5.1. Effect of off-state turn-on on eye-diagrams 107
4.5.2. Effect of off-state turn-on on timing jitter 110
4.6. Summary 112
CHAPTER V: ELECTROSTATIC DISCHARGE-INDUCED
DEGRADATION OF ELEVATED-OXIDE VCSELS 115
5.1. Introduction 115
5.2. Test setup and procedure 119
5.3. ESD-induced degradation: Phenomena 121
5.3.1 Changes in the electro-optical characteristics by forward ESD 121
5.3.2. Changes in the electro-optical characteristics by reverse ESD 128
5.3.3. Development of forward ESD-induced degradation 135
5.3.4. Development of forward ESD-induced degradation 139
5.4. ESD-induced degradation: Review 148
5.4.1 Forward ESD-induced degradation 148
5.4.2. Reverse ESD-induced degradation 153
5.5. ESD damage threshold of elevated-oxide VCSELs 156
5.6. Summary 159
CHAPTER VI: CONCLUSION 161
6.1. Summary 161
6.2. Future works 164
APPENDICES 165
A. Transfer matrix method 165
A.1 Transfer matrix method 165
A.2. Lasing condition 169
A.3. Generation and loss of optical power 171
B. Current component analysis using an equivalent circuit model 175
B.1 Equivalent circuit model of oxide VCSELs 181
B.2. Forward ESD-induced degradation 184
B.3. Reverse ESD-induced degradation 197
BIBLIOGRAPHY 204
VITA 212
LIST OF PUBLICATIONS 213
