MICROELECTRONIC DEVICES AND CIRCUITS - …

1 MICROELECTRONIC DEVICES AND CIRCUITS 2006 electronic Edition Clifton G. Fonstad Department of Electrical Engineering and Computer Science Massachusetts Institute of Technology Copyright 0 2006 by Clifton G. Fonstad. All rights reserved, MICROELECTRONIC DEVICES and CIRCUITS , 2006 electronic EditionCopyright 2006 by Clifton G. Fonstad. All rights under Creative Commons License , which is available You are free to copy, distribute, display, and perform the work under the followingconditions:Attribution - You must attribute the work indicating the title is "MicroelectronicDevices and CIRCUITS , 2006 electronic Edition" and that it has been authored,published, copyrighted, and licensed by Clifton G. - You may not use this work for commercial Derivative Works -You may not alter, transform, or build upon this work.

2 For any reuse or distribution, you must make clear to others the license terms ofthis work. Any of these conditions can be waived if you get permission from the copyrightholder. Your fair use and other rights are in no way affected by the above. This is a human-readable summary of the Legal Code; the full license can beviewed :This book is based on the textbook MICROELECTRONIC DEVICES and Circuitsby Clifton G. Fonstad, which was published by McGraw-Hill in Library of Congress cataloging-in-publication data for that book isreproduced below:Fonstad, Clifton DEVICES and CIRCUITS / Clifton G. Fonstadp. cm. (McGraw-Hill series in electrical and computerengineering. Electronics and VLSI CIRCUITS .)Includes 0-07-021496-41. Microelectronics. 2. Electric circuit analysis. 3. Electriccircuits, Nonlinear.

3 I. Title. II. SeriesTK has declared the original textbook out of print andhas transferred the copyright to the author, Clifton in the original text identified as of August 15, 2006 have beencorrected in this edition will appear enlarged 110% from the original page size whenprinted on standard letter paper ( x 11 ).CONTENTS Preface 1 Modeling General Comments Empirical Device Models Why Semiconductors? Why Transistors? Thermal Equilibrium Intrinsic Silicon Extrinsic Silicon 2 Uniform Semiconductors in Equilibrium Donors and Acceptors Detailed Balance Equilibrium Carrier Concentration Elemental Semiconductors Compound Semiconductors Additional Semiconductors Summary Uniform Electric Field: Drift The Effects of Changing Temperature 3 Uniform Excitation of Semiconductors Drift Motion and Mobility Drift Current and Conductivity 3, Uniform Optical Excitation Minority Carrier Lifetime Population Transients Basic Concepts Specific Device Issues Temperature Variation of Mobility and Conductivity High-Level Injection Populations and Transients Photoconductivity and Photoconductors Summary ix 1 1 3 4 7 7 9 14 14 17 21 22 22 22 24 25 31 31 31 34 37 37 38 40 45 48 48 49 53 iii iv CONTENTS 4 Nonuniform Situations.

4 The Five Basic Equations Diffusion A Model for Diffusion Diffusion Current Density Modeling Nonuniform Situations Total Current Densities The Continuity Equations Gauss s Law The Five Basic Equations Other Diffusion Important in DEVICES Summary 5 Nonuniform Carrier Injection: Flow Problems Developing the Diffusion Equation Uniformly Doped Extrinsic Material Low-Level Injection Quasineutrality Minority Carriers Flow by Diffusion Time-Dependent Diffusion Equation Quasistatic Diffusion: Flow Problems Homogeneous Solutions Particular Solutions Boundary Conditions The Total Current Specific Situations The Currents, Electric Field, and Net Charge Flow Problems summary in Thermal Equilibrium 6 Nonuniformly Doped Semiconductors General Description: The Poisson-Boltzmann Equation Gradual Spatial Variation of Doping p-n Junction: The Depletion Approximation Abrupt p-n Junction Other p-n Junction Profiles Summary Depletion Region Changes Depletion Capacitance Diffusion Capacitance The Electrostatic Potential around a circuit 7 Junction Diodes Applying Voltage to a p-n Junction Depletion Width Variation with Voltage Applications of the Depletion Capacitance Excess Populations at the Depletion Region Edges Current-Voltage Relationship for an Ideal Diode Limitations to the Simple Model Current Flow 61 61 62 63 63 64 64 65 66 66 67 71 71 72 72 73 75.

5 76 76 78 78 80 80 83 85 96 100 109 110 113 115 116 123 124 126 131 131 133 134 134 137 139 141 144 151 154 circuit Models for Junction Diodes Large-Signal Models Static Small-Signal Linear Models Solar Cells and Photodiodes Optical Excitation of p-n Diodes Applications of Illuminated p-n Diodes Light-Emitting Diodes Summary 8 Bipolar Junction Transistors The Ebers-Moll Model for Uniformly Doped One-Dimensional BJTs Superposition The Forward Portion (vgc = 0) The Reverse Portion (vg~ = 0) Full Solution: The Ebers-Moll Model Characteristics and Operating Regions Basic Transistor Design Large-Signal Models Static Small-Signal Linear Models Dynamic Small-Signal Transistor Models Beyond Ebers-Moll: Limitations of the Model circuit Models for Bipolar Junction Transistors Phototransistors Summary 9 The MOS Capacitor The MOS Capacitor in Thermal Equilibrium Isolated MOS Capacitor with Applied Voltage Flat-band Accumulation Depletion Threshold and Inversion Adjacent p-n Junction Biased MOS Capacitor with Contact to the Channel Direct Contact to the Channel Capacitance of MOS Capacitors versus Bias Ions and Interface Charges in MOS Structures Interface Charge Oxide Charge Types of MOS Capacitors n-channel, p-type Si p-channel.

6 N-type Si summary 10 Field Effect Transistors CONTENTS V 157 157 162 166 167 169 173 174 185 187 187 188 192 194 195 200 203 208 208 218 224 227 23 1 24 1 24 1 242 243 245 246 247 249 249 252 252 257 257 25 8 259 260 260 26 1 265 Metal-Oxide-Semiconductor Field Effect Transistors 266 Large-Signal Model: The Gradual Channel Approximation 268 Static Small-Signal Linear Model 287 vi CONTENTS Junction Field Effect Transistors Large-Signal Model Static Small-Signal Linear Model High-Frequency Small-Signal Model Metal-Semiconductor Field Effect Transistors Basic Concept and Modeling Velocity Saturation in MESFETs 11 Single-Transistor Linear Amplifier Stages Summary Biasing Transistors Bipolar Transistor Biasing Field-Effect Transistor Biasing The Concept of Mid-band Single-Bipolar-Transistor Amplifiers Common-Emitter Stage Degenerate-Emitter Stage Common-Base Stage Emitter-Follower Stage Common-Source Stage.

7 Degenerate-source Common-gate Source-follower Single Field Effect Transistor Amplifiers Summary 12 Differential Amplifier Stages Basic Topology Large-Signal Analysis Bipolar Differential Amplifier Transfer Characteristic MOSFET Differential Amplifier Transfer Characteristic . Difference and Common Mode Inputs Small-Signal Linear Analysis Half- circuit Techniques Difference and Common Mode Voltage Gains Current Gains Input and Output Resistances Current Source Designs Outputs, Current Mirrors, and Active Loads Bipolar Current Sources MOSFET Current Sources Summary 13 Multistage Amplifiers Capacitively Coupled Cascade Direct-Coupled Amplifiers Direct-Coupled Cascade Cascode Darlington Emitter/Source-Coupled Cascode Complementary Output 296 297 303 305 305 305 307 313 317 318 318 322 325 327 3 29 338 341 343 345 346 3 60 361 362 363 373 373 375 376 378 381 382 382 3 87 3 90 39 1 392 395 396 400 403 413 414 419 419 422 424 430 433 CONTENTS Multistage Differential Amplifiers A Design Exercise.

8 A Basic npn Op-Amp The Parts The Whole Darlington Second Stage p-MOS Current Mirror and Second Stage Beyond Basic: Design with BiCMOS Summary 14 High-Frequency Analysis of Linear Amplifiers Determining the Bounds of the Mid-Band Range Method of Open- circuit Time Constants Method of Short- circuit Time Constants Common-EmitterLSource The Miller Effect Degenerate-EmitterBource Ernitter/Source-Follower Common-Base/Gate Cascode Darlington Pair Bipolar Transistors Field Effect Transistors Examination of Specific circuit Topologies Intrinsic High-Frequency Limits of Transistors Summary Generic Binary Logic CIRCUITS 15 Digital Building-Block CIRCUITS Generic Inverter Objectives in Inverter Design Determining the Transfer Characteristic Resistor Load Enhancement Mode Loads Depletion Mode Load: n-MOS Complementary Load.

9 CMOS The Simple Bipolar Inverter Transistor-Transistor Logic: TTL Emitter-Coupled Logic: ECL Static Memory Cells Dynamic Memory Cells Realizing Logic Functions with Inverters MOSFET Logic Bipolar Inverters Memory Cells Summary 16 Switching Transients in DEVICES and CIRCUITS General Techniques nrning DEVICES On and Off Bipolar Junction DEVICES Field Effect DEVICES vii 437 443 443 447 449 452 454 457 465 465 466 467 468 468 472 476 47 6 479 48 1 483 484 484 487 493 499 500 500 50 1 504 509 510 51 1 514 516 521 524 525 527 531 534 535 538 540 547 548 550 551 561 viii CONTENTS Inverter Switching Times and Gate Delays CMOS and Other MOSFET Inverters mL and ECL Gates Device and circuit Scaling Summary Some Representative Properties of Common Senliconductors Seeing Holes and Electrons Appendixes A.

10 B B. 1 Hall Effect Measurement C. 1 Energy Bands Effective Mass Theory Quantifying the Tendency to Quasineutrality D. 1 Non-uniform Static Excitation: LD, E Metal-Semiconductor Contacts and DEVICES E. 1 Reverse Biased Metal-Semiconductor Junctions Forward Bias and Currents Schottky Diodes Ohmic Contacts Hot Point Probe Measurement C Some Important Concepts of Solid-state Physics D Uniform Time-varping Excitation: TD The Metal-Semiconductor Junction in Thermal Equilibrium F G Integrated circuit Fabrication G. Crystal Growth Doping G. Encapsulation G. Microlithography G. Metallization Etching and Cleaning Dielectrically Isolated Bipolar Technologies Silicon-Gate nMOS Processing A Silicon-Gate CMOS Process BiCMOS GaAs EnhancementIDepletion Mode Large- and Small-signal Values of ,8 G.