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Publié par | universitat_duisburg-essen |
Publié le | 01 janvier 2009 |
Nombre de lectures | 33 |
Langue | English |
Poids de l'ouvrage | 7 Mo |
Extrait
Solid-State Imaging in Standard CMOS
Processes
Von der Fakultät für Ingenieurwissenschaften
der Universität Duisburg-Essen
zur Erlangung des akademischen Grades eines
Doktors der Ingenieurwissenschaften
genehmigte Dissertation
von
Daniel Durini Romero
aus
Belgrad
Referent: Prof. Bedrich J. Hosticka, Ph.D.
Korreferent: Prof. Dr. rer. nat. Dieter Jäger
Tag der mündlichen Prüfung: 03.02.2009
Acknowledgements
his thesis was written as a part of the activities developed at the chair
Microelectronic Systems (MES) of the University of Duisburg-Essen, in T collaboration with the Photodetector Arrays group, which forms part of the
department Signal Processing and System Development (SYS) at the Fraunhofer
Institute of Microelectronic Circuits and Systems (Fraunhofer IMS) in Duisburg,
Germany. My almost four-year long stay in Germany, required to develop this
investigation, was supported by the German Academic Exchange Service
(DAAD), to whom I would never be able to thank enough for this marvellous
and multifaceted experience.
My deepest gratitude goes to my research advisor, Prof. Bedrich J. Hosticka,
Ph.D., for his enthusiastic support, invaluable discussions and continuous
encouragement. The same goes to both group leaders I had the privilege to
work with, Armin Kemna and Werner Brockherde.
I would also like to profoundly thank Prof. Dr. Holger Vogt and Prof. Dr. Anton
Grabmaier for their support and the suggestions regarding different aspects of
this work.
My gratitude goes also to Prof. Dr. Dieter Jäger for his readiness to become the
second examiner of this work.
This investigation would have never been completed without the unique
interest, hours of discussion, suggestions, and unforgettable brainstorming
sessions of the entire SYS department, which proved to be an invaluable well of
experience and help. I would like to thank all of them, and specially Christian
Nitta, Wiebke Ulfig, Erol Özkan, Cornelia Metz, Frank Matheis, Salahedine
Ibnouquassai, Omar Elkhalili, Andreas Spickermann, Olaf Schrey, Sascha Thoß,
Stefan Bröcker, and Melanie Jung.
Many thanks also to Suzanne Linnenberg, Stefan Dreiner, Ralf Rudolph, Dirk
Dietrich, Andrea Kahlen, Peter vom Stein, and Martin Figge for their help.
I would like to thank my family for their continuous, neverending love and
support. Many things in my life would have never been possible without their
presence.
Finally, I thank my wife Lizette for her unlimited patience and lovingly support in
this incredible adventure. I could not wish for a better “accomplice”. This work
is dedicated to her.
Daniel Durini, Solid-state Imaging in Standard CMOS Processes Table of Contents
________________________________________________________________________________________________________
Table of Contents
TABLE OF FIGURES .................................................................................................IV
Chapter 1 .................................................................................................iv
Chapter 2 .................................................................................................iv
Chapter 3 ...............................................................................................viii
Chapter 4 ................................................................................................. x
Chapter 5 .................................................................................................xi
Chapter 6 ................................................................................................xii
INTRODUCTION .....................................................................................................1
CHAPTER 1: FUNDAMENTALS OF SILICON-BASED PHOTODETECTION ..................................4
1.1 Energy Band Structure in Silicon...........................................................4
1.2 Carrier Concentration in Silicon in Thermal Equilibrium........................9
1.3 Fundamentals of Silicon-Based Phototransduction .............................10
1.4 Silicon-Based Photodetectors.............................................................14
1.4.1 p-n Junction Based Photodetector Structures ............................15
1.4.2 Metal-Oxide-Semiconductor Capacitor (MOS-C) based
Photodetector Structures ...........................................................23
1.5 Silicon-Based Standard Imaging Technologies....................................30
1.5.1 Charge-Coupled Devices (CCD) ................................................31
1.5.2 Comparison of CCD and CMOS Imaging Technologies .............32
CHAPTER 2: THE 0.5μm STANDARD CMOS PROCESS AND ITS PHOTODETECTION
POSSIBILITIES ......................................................................................33
2.1 Meeting the 0.5μm Standard CMOS Process .....................................33
2.2 The Inter-Metal Isolation and Passivation Layer Influence on the
Photodetectors Optical Sensitivity ......................................................35
2.3 Minority Carrier Lifetimes..................................................................48
2.3.1 The Pulsed MOS-C Measuring Method Used to Experimentally
Determine the Generation Lifetimes and Generation Surface
Velocities Present in the 0.5μm Standard CMOS Process ............51
2.3.1.1 Experimental Results Obtained for the n-Type MOS-C
Fabricated on p-Epi (substrate) in the 0.5μm CMOS Process54
2.3.1.2 Experimental Results Obtained for the p-Type MOS-C
Fabricated on n-well in the 0.5μm CMOS Process ..............56
2.3.2 Minority Carriers Recombination Lifetime and Diffusion Length
Measurements Based on the Steady-State Short-Circuit Optical
Method.....................................................................................58
2.4 Reverse Biased p-n Junction Based Photodetectors Fabricated in the
0.5μm Standard CMOS Process Under Investigation...........................61
2.4.1 Reverse Biased p-n Junction Based Photodetector Dark Current
Considerations ..........................................................................61
2.4.2 n-well Photodiode (n-well PD)...................................................64
2.4.3 Buried Photodiode (BPD)...........................................................66
+ +2.4.4 n Photodiode (n PD)...............................................................68
2.4.5 Reverse Biased p-n Junction Based Photodetectors Electrical and
Optical Characterization ............................................................70
_______________________________________________________________ i Daniel Durini, Solid-state Imaging in Standard CMOS Processes Table of Contents
________________________________________________________________________________________________________
2.4.5.1 Dark Current (I-V) Measurements........................................70
2.4.5.2 Capacitance (C-V) Characterization .....................................77
2.4.5.3 Optical Sensitivity and Quantum Efficiency Measurements...80
2.4.5.4 UV-Enhanced Quantum Efficiency Photodiode Stripes .........82
2.5 MOS-C Based Photodetector Structures Fabricated in the 0.5μm
Standard CMOS Process Under Investigation......................................85
2.5.1 MOS-C Based Photodetector Dark Current Considerations........85
2.5.2 n-type Photogate (n-type PG)....................................................88
2.5.3 p-type Photogate (p-type PG)....................................................90
2.5.4 Electrical and Optical characterization of MOS-C Based Photogate
Detectors ..................................................................................92
2.5.4.1 Dark current (I-V) Measurements.........................................92
2.5.4.2 Optical Sensitivity and Quantum Efficiency Measurements...93
2.6 Indium-Tin-Oxide (ITO) Layer Used for Fabrication of Semi Transparent
Photogates in the 0.5μm Standard CMOS Process Under
Investigation......................................................................................96
2.6.1 Integration of the ITO Layer Deposition in the 0.5μm CMOS
Process Under Investigation .......................................................98
CHAPTER 3: PIXEL CONFIGURATIONS IN THE 0.5μM CMOS PROCESS............................105
3.1 Signal-to-Noise Ratio (SNR) Issues in Active Pixel Sensors .................106
3.2 Time-of-Flight 3-D Imaging in the 0.5μm Standard CMOS Process...116
3.3 Possibilities of Charge-Coupling the Separated Photoactive and Readout
Node Regions in Different Active Pixel Configurations Fabricated in the
0.5μm CMOS Process ......................................................................120
3.3.1 Reverse-Biased p-n Junction Based Active Pixels with Separated
Charge-Coupled Photoactive and Readout Regi