This book explores the operating principles of complementary metal oxide semiconductor (CMOS) image sensors, their architecture, readout circuits, and characterisation techniques.
The book focusses on the pinned photodiode (4T) pixel and also describes the three transistor (3T) design and other pixel architectures. Device operation is explained throughout with the support of technology computer-aided design (TCAD) semiconductor simulations.
Characterisation techniques of CMOS image sensors are discussed in detail, including the use of the photon transfer curve (PTC) for determining the many device parameters. Solved examples are included with the purpose of helping readers gain an understanding of the practical use of the formulas. The main audience includes physicists and engineers in image sensor characterisation and development.
Author(s): Konstantin D. Stefanov
Publisher: IOP Publishing
Year: 2022
Language: English
Pages: 300
City: Bristol
PRELIMS.pdf
Preface
Acknowledgement
Author biography
Konstantin D Stefanov
List of frequently used abbreviations
Table of common symbols and units
CH001.pdf
Chapter 1 The fundamentals
1.1 Introduction—what is an image sensor and what does it do?
1.2 Charge generation
1.2.1 Photoeffect
1.2.2 Ionisation
1.3 Charge collection
1.3.1 Carrier lifetime
1.3.2 Recombination
1.3.3 Drift
1.3.4 Diffusion
1.4 Charge transfer
1.5 Charge conversion
1.6 pn junction
1.6.1 pn junction in equilibrium
1.6.2 pn junction under reverse bias
1.6.3 Charge collection
1.6.4 Junction capacitance
1.7 MOS capacitor
1.7.1 Depletion
1.7.2 Gate capacitance
1.8 MOS transistor
1.8.1 Structure
1.8.2 MOSFET characteristics
1.8.3 Output resistance and body effect
1.8.4 Transistor threshold
1.8.5 Analogue switch
1.8.6 MOSFET capacitor
1.9 Source follower
1.9.1 Gain
1.9.2 Input capacitance
Chapter summary
References
CH002.pdf
Chapter 2 CMOS pixel architectures
2.1 History and technology
2.2 Photodiode APS
2.2.1 Structure
2.2.2 Operation
2.2.3 Performance
2.3 Pinned photodiode (4T)
2.3.1 Structure
2.3.2 Operation
2.3.3 Charge storage and full well capacity
2.3.4 Charge transfer
2.3.5 Image lag
2.3.6 Transistor sharing
2.4 Other PPD-based pixels
2.4.1 Global reset (5T)
2.4.2 In-pixel signal storage
2.4.3 High dynamic range
2.5 Hybrid and 3D image sensors
Chapter summary
References
CH003.pdf
Chapter 3 Advanced image sensor topics
3.1 Photocurrent
3.2 Dark current
3.2.1 Sources of dark current
3.2.2 Depletion dark current
3.2.3 Diffusion dark current
3.2.4 Surface dark current
3.2.5 Dark current suppression by pinning
3.2.6 Temperature for dark current doubling
3.3 Reflective barrier
3.4 Back-side illumination
3.4.1 Front and back-side illumination
3.4.2 Back-side interface
3.4.3 BSI technologies
3.5 Depletion depth and potential gradients
3.5.1 Depletion depth as a 3D effect
3.5.2 Potential gradients in PPDs
3.6 Punch-through
3.7 Field-induced junctions
Chapter summary
References
CH004.pdf
Chapter 4 Noise and readout techniques
4.1 Noise in image sensors
4.1.1 Thermal and reset noise
4.1.2 Shot noise
4.1.3 1/f and random telegraph noise
4.1.4 MOSFET noise
4.1.5 Source follower noise
4.2 Correlated double sampling
4.2.1 Reset noise suppression
4.2.2 Double sampling
4.2.3 Dual slope integrator
4.2.4 Optimal signal processing
4.2.5 Digital CDS and multiple sampling
4.2.6 Column-level noise
4.2.7 MOSFET optimisation
Chapter summary
References
CH005.pdf
Chapter 5 Characterisation
5.1 Introduction
5.2 Readout modes
5.3 Principles of EO characterisation
5.4 Photoresponse, non-uniformity and nonlinearity
5.5 Photon transfer curve
5.5.1 Principles
5.5.2 Frame differencing
5.5.3 System gain, CVF and noise
5.5.4 Nonlinear PTC
5.5.5 PTC from dark current
5.5.6 Practical tips for the PTC
5.5.7 The PTC as a diagnostic tool
5.6 X-ray calibration
5.7 Full well capacity and dynamic range
5.8 Dark current and DSNU
5.9 Noise measurement
5.10 Image lag
5.11 Quantum efficiency
5.11.1 Principles
5.11.2 Pain–Hancock method
5.11.3 Modulation transfer function
5.12 Electrical transfer function
Chapter summary
References
CH006.pdf
Chapter 6 Electronics
6.1 On-chip electronics
6.1.1 Architecture
6.1.2 Column buffers
6.1.3 Column amplifiers
6.1.4 CDS circuits
6.1.5 Row drivers
6.1.6 Pixel addressing
6.1.7 Analogue switches and multiplexers
6.1.8 Output amplifier
6.2 Off-chip electronics
6.2.1 General requirements
6.2.2 Signal amplifiers
6.2.3 Power supplies
6.2.4 Bias circuits
6.2.5 Noise measurements
Chapter summary
References
