Silicon-on-Sapphire Circuits and Systems: Sensor and Biosensor Interfaces Book

Acknowledgments xiii

Preface xv

1 The Silicon-on-Sapphire Fabrication Process 1

1.1 Introduction 1

1.2 Why SOI? 2

1.3 The SOS Fabrication Process 3

1.3.1 Advantages of SOS 5

1.3.2 Disadvantages of SOS 6

1.4 SOS Wafer Manufacturing 6

1.5 Peregrine SOS Process Features 9

1.5.1 Local Isolation 10

1.5.2 Fully Depleted Devices 10

1.6 MOS Devices in the Peregrine SOS Process 11

1.7 SOS MOS Characteristics for Analog Design 14

1.7.1 Transistor Transconductance Parameter 15

1.7.2 Modeling the Subthreshold Region 20

1.7.3 Leakage Data 28

1.7.4 Above-threshold Statistical Characteristics 28

1.7.5 Subthreshold Statistical Characteristics 32

1.7.6 Comparison Between Data and Simulation of SOS Mosfets 34

1.8 Summary 38

2 SOS Mosfet Modeling 39

2.1 Introduction 39

2.2 A Model of the SOS Mosfet in Strong Inversion 40

2.2.1 Strong Inversion Model 41

2.2.2 Strong Inversion Model Results and Discussion 41

2.3 Hot Electron Effects in SOS Mosfets 48

2.3.1 Standard Hot-Electron Effects Models 54

2.3.2 Hot Carrier Generated Kink Effect Modeling of SOS Devices 57

2.3.3 Results and Discussion 62

2.4 EKV Model and Parameter Extraction 63

2:4.1 The EKV Model 64

2.4.2 EKV Model Results and Discussion 67

2.5 Models of SOS Four Terminal Mosfets Operated as Bipolar Transistors 71

2.5.1 Modeling Bipolar Devices in SOS 71

2.5.2 A Chance for Bicmos SOS? 76

2.6 SOS Flash Memory Devices 77

2.6.1 SOS Flash Memory Design 78

2.6.2 SOS Flash Memories Experimental Results 80

2.6.3 SOS Flash Memories Performance Evaluation and Model 84

2.7 Conclusions 86

2.8 Data Collection Methods 87

3 Design of SOS Single-Stage Amplifiers and AnalogComponents 89

3.1 Introduction 89

3.2 Analog Characteristics of SOS Mosfets 89

3.3 SOS Current Mirrors 94

3.4 SOS Supply-Independent Current Reference 97

3.5 SOS Single-Stage Amplifiers 98

3.5.1 SOS Common-Source Amplifiers 99

3.5.1.1 SOS Common-Source Amplifiers with Diode-Connected Mosfet Loads 99

3.5.1.2 SOS Common-Source Amplifiers with Current-Source Load 104

3.5.2 SOS Cascoded Common-Source Amplifiers 107

3.5.3 SOS Source-Follower Amplifiers 111

3.6 SOS Differential Amplifiers 116

4 Design of SOS Operational Amplifiers, Comparators, and Voltage References 125

4.1 Operational Amplifiers in SOS 125

4.2 Comparator Circuits in SOS 131

4.2.1 SOS High-Performance Comparators 133

4.2.2 SOS Low-power Comparator 136

4.3 SOS Bandgap References 138

5 Digital Circuit Design in SOS 145

5.1 Introduction 145

5.2 SOS Inverter Characteristics 145

6 Design of SOS Data Converters 155

6.1 Introduction 155

6.2 SOS DACs 156

6.2.1 SOS Capacitive DAC Converters 156

6.2.2 SOS Capacitive DAC Accuracy 157

6.2.2.1 The Split-Array Capacitive DAC 159

6.2.2.2 The C-2C Ladder Capacitive DAC 160

6.2.2.3 Layout of SOS Capacitive DACs 162

6.2.3 SOS Resistive DACs 163

6.3 SOS DACs 164

6.3.1 SOS Successive Approximation Analog-to-Digital Converters 165

6.3.2 0peration of a SAR 167

6.3.3 Capacitive Ladder and Charge Scaling 170

6.3.4 SAR ADC Design in SOS and Optimization 171

6.3.4.1 Design of Capacitor Array in SOS 172

6.3.4.2 Input Switches, Logic, and SAR: SOS Design 173

6.3.4.3 Comparator 174

6.3.5 A High-Performance 8-Bit SAR ADC 174

6.3.6 A High-Precision 10-Bit SOS SAR ADC 179

6.3.7 A Low-Power 8-bit SOS SAR ADC 181

6.3.8 A C-2C Ladder Ultralow Power SOS SAR ADC 186

6.3.9 SOS SAR ADC Summary 189

6.4 SOS Asynchronous ΣΔ Analog to Digital Converters 189

6.4.1 Result in SOS Technology 193

6.5 Summary 195

7 Photosensitive Circuits 197

7.1 Introduction 197

7.1.1 Advantages of SOS Photodetectors and Image Sensors 198

7.2 Photodetector Design: General Theory 199

7.2.1 Quantum Efficiency 200

7.2.2 Photodiode Photocurrent Models 202

7.3 Photodiode Design in a Bulk CMOS Process 204

7.3.1 Generation Rate, Diffusion Coefficients, and Electron Mobility 204

7.3.2 Characterization of the Depletion Region 205

7.3.3 Quartum Efficiency and Responsivity 206

7.4 SOS Photodetectors 207

7.4.1 SOS PN Photodiodes 208

7.4.1.1 Measured Characteristics of an SOS PN Photodiode 209

7.4.2 SOS Phototransistors 213

7.4.2.1 SOS Phototransistor Measured Characteristics 213

7.4.3 SOS PIN Photodiodes 216

7.4.3.1 SOS PIN Photodiode Model 218

7.4.3.2 Measured Characteristics of an SOS PIN Photodiode 223

7.5 Conclusions 227

8 SOS Address-Event Image Sensor 229

8.1 Introduction 229

8.2 Overview of Photosensitive Circuits 230

8.2.1 Active Pixels 231

8.2.2 Photodiodes and Active Pixel Operation 232

8.2.3 Active Pixel Sensors 233

8.3 Noise Sources in Phototransducing Circuits 234

8.3.1 Temporal Noise 235

8.3.2 Pixel and Photodiode Design and Noise Optimization 236

8.4 Design of an SOS APS 237

8.4.1 SOS APS System Overview 237

8.4.2 SOS APS Testing and Characterization 241

8.4.3 SOS APS Array with Phototransistor Detector 246

8.4.4 Ultraviolet Testing 249

8.5 Design of an SOS Digital Image Sensor Array 250

8.5.1 Digital Pixel Design 252

8.5.2 Photodiode Design and Characterization 254

8.5.3 System Architecture 256

8.5.4 SOS Digital Image Sensor Testing and Characterization 260

8.6 Summary 263

9 SOS Biosensor Interfaces 265

9.1 Introduction 265

9.2 Noise and Sensing Limits 266

9.2.1 Low-Voltage Measurements Limits 267

9.2.2 Low-Current Measurements Limits 267

9.2.3 Voltage-Mode Biosensor Interfaces and Noise Performance 270

9.2.4 Current-Mode Biosensor Interfaces and Noise Performance 271

9.2.4.1 Resistive Feedback Current-Measuring Headstage 272

9.2.4.2 Linear Integrator Current-Measuring Headstage 274

9.2.4.3 Follower Integrator Current-Measuring Headstage 276

9.2.4.4 Current Conveyor Current-Measuring Headstage 277

9.2.5 Measurement Setup 279

9.3 SOS Current-Mode Biosensor Interfaces 282

9.3.1 Integrating Current-Measuring Interfaces 283

9.3.1.1 System Components 284

9.3.1.2 Input-Referred Noise Analysis 287

9.3.1.3 Results 289

9.3.1.4 Experiments 295

9.3.2 SOS Continuous-Time Current-Mode Biosensor Interfaces 300

9.3.2.1 Continuous-Time Current-Measuring System Overview 301

9.3.2.2 Noise in the Continuous-Time Current-Measuring System 308

9.3.2.3 Hardware Test Bed 312

9.3.2.4 Experimental Results 313

9.4 SOS Voltage-Mode Biosensor Interfaces 316

10 SOS Design of Isolation and Three-Dimensional Circuits 323

10.1 Intoduction 323

10.2 IsoIation Circuits in SOS 324

10.2.1 Monolithic Isolation Techniques 325

10.2.2 Capacitively Isolated Circuits in SOS 326

10.2.2.1 SOS Capacitive Isolator with Differential Transmission 329

10.2.2.2 SOS Isolation Charge Pump 333

10.2.2.3 SOS Differential Capacitive Isolator Measurements and Results 337

10.2.2.4 Application of the SOS Isolator: Isolated Power Supply Feedback 342

10.2.3 Digital Phase-Shift-Modulated Isolation Buffer in SOS 347

10.2.3.1 Digital Phase-Shift-Modulated Isolation Buffer System Overview 348

10.2.3.2 Digital Phase-Shift-Modulated Isolation Buffer Results and Measurements 350

10.2.4 Inductively Coupled Isolated Circuits 352

10.2.4.1 Transmitter Circuit: LC-Tank Oscillator 353

10.2.4.2 LC-tank Oscillator Model 354

10.2.4.3 Effective Resistance and Minimum Transconductance 356

10.2.4.4 Transformer Design 357

10.2.4.5 Active Devices and Transconductance 360

10.2.4.6 Receiver Circuit 362

10.2.4.7 Electromagnetic Isolator: Conclusions 363

10.3 Three-Dimensional Circuits in SOS 363

10.3.1 Three-Dimensional Interdie Capacitive Data Communication and Power Transfer 364

10.3.1.1 Three-Dimensional System Overview 365

10.3.1.2 Three-Dimensional Circuits Results and Measurements 368

10.3.2 Three-Dimensional Integrated Sensors in SOS 373

10.3.2.1 Three-Dimensional Integrated Sensor Components 375

10.3.2.2 Three-Dimensional Integrated Sensors Results and Measurements 376

10.4 Summary and Conclusions 378

References 381

Index 391