Fundamentals of Modern VLSI Devices

by Yuan Taur , Tak H. Ning

• ISBN13: 9780521832946
• ISBN10: 0521832942
• Edition: 2nd
• Format: Hardcover
• Copyright: 2009-08-28
• Publisher: Cambridge University Press

Summary

Learn the basic properties and designs of modern VLSI devices, as well as the factors affecting performance, with this thoroughly updated second edition. The first edition has been widely adopted as a standard textbook in microelectronics in many major US universities and worldwide. The internationally-renowned authors highlight the intricate interdependencies and subtle tradeoffs between various practically important device parameters, and also provide an in-depth discussion of device scaling and scaling limits of CMOS and bipolar devices. Equations and parameters provided are checked continuously against the reality of silicon data, making the book equally useful in practical transistor design and in the classroom. Every chapter has been updated to include the latest developments, such as MOSFET scale length theory, high-field transport model, and SiGe-base bipolar devices.

Author Biography

Yuan Taur is a Professor of Electrical and Computer Engineering at the University of California, San Diego. He spent 20 years at IBM's T.J. Watson Research Center where he won numerous invention and achievement awards. He is an IEEE Fellow, Editor-in-Chief of IEEE Electron Device Letters, and holds 14 US patents. Tak H. Ning is an IBM Fellow at the T.J. Watson Research Center, New York, where he has worked for over 35 years. He is a Fellow of the IEEE and the American Physical Society, a member of the US National Academy of Engineering, and holds 36 US patents.

Table of Contents

Preface to the first edition	p. xi
Preface to the second edition	p. xiii
Physical constants and unit conversions	p. xv
List of symbols	p. xvi
Introduction	p. 1
Evolution of VLSI Device Technology	p. 1
Historical Perspective	p. 1
Recent Developments	p. 4
Modern VLSI Devices	p. 4
Modern CMOS Transistors	p. 4
Modern Bipolar Transistors	p. 5
Scope and Brief Description of the Book	p. 6
Basic Device Physics	p. 11
Electrons and Holes in Silicon	p. 11
Energy Bands in Silicon	p. 11
n-Type and p-Type Silicon	p. 17
Carrier Transport in Silicon	p. 23
Basic Equations for Device Operation	p. 27
p-n Junctions	p. 35
Energy-Band Diagrams for a p-n Diode	p. 35
Abrupt Junctions	p. 38
The Diode Equation	p. 46
Current-Voltage Characteristics	p. 51
Time-Dependent and Switching Characteristics	p. 64
Diffusion Capacitance	p. 70
MOS Capacitors	p. 72
Surface Potential: Accumulation, Depletion, and Inversion	p. 72
Electrostatic Potential and Charge Distribution in Silicon	p. 78
Capacitances in an MOS Structure	p. 85
Polysilicon-Gate Work Function and Depletion Effects	p. 91
MOS under Nonequilibrium and Gated Diodes	p. 94
Charge in Silicon Dioxide and at the Silicon-Oxide Interface	p. 98
Effect of Interface Traps and Oxide Charge on Device Characteristics	p. 103
Metal-Silicon Contacts	p. 108
Static Characteristics of a Schottky Barrier Diode	p. 108
Current Transport in a Schottky Barrier Diode	p. 115
Current-Voltage Characteristics of a Schottky Barrier Diode	p. 115
Ohmic Contacts	p. 120
High-Field Effects	p. 122
Impact Ionization and Avalanche Breakdown	p. 122
Band-to-Band Tunneling	p. 125
Tunneling into and through Silicon Dioxide	p. 127
Injection of Hot Carriers from Silicon into Silicon Dioxide	p. 133
High-Field Effects in Gated Diodes	p. 135
Dielectric Breakdown	p. 137
Exercises	p. 141
Mosfet Devices	p. 148
Long-Channel Mosfets	p. 148
Drain-Current Model	p. 149
Mosfet I-V Characteristics	p. 155
Subthreshold Characteristics	p. 163
Substrate Bias and Temperature Dependence of Threshold Voltage	p. 166
Mosfet Channel Mobility	p. 169
Mosfet Capacitances and Inversion-Layer Capacitance Effect	p. 172
Short-Channel Mosfets	p. 175
Short-Channel Effect	p. 176
Velocity Saturation and High-Field Transport	p. 186
Channel Length Modulation	p. 195
Source-Drain Series Resistance	p. 196
Mosfet Degradation and Breakdown at High Fields	p. 196
Exercises	p. 201
CMOS Device Design	p. 204
Mosfet Scaling	p. 204
Constant-Field Scaling	p. 204
Generalized Scaling	p. 207
Nonscaling Effects	p. 210
Threshold Voltage	p. 212
Threshold-Voltage Requirement	p. 213
Channel Profile Design	p. 217
Nonuniform Doping	p. 224
Quantum Effect on Threshold Voltage	p. 234
Discrete Dopant Effects on Threshold Voltage	p. 239
Mosfet Channel Length	p. 242
Various Definitions of Channel Length	p. 242
Extraction of the Effective Channel Length	p. 244
Physical Meaning of Effective Channel Length	p. 248
Extraction of Channel Length by C-V Measurements	p. 252
Exercises	p. 254
CMOS Performance Factors	p. 256
Basic CMOS Circuit Elements	p. 256
CMOS Inverters	p. 256
CMOS NAND and NOR Gates	p. 266
Inverter and NAND Layouts	p. 270
Parasitic Elements	p. 273
Source-Drain Resistance	p. 274
Parasitic Capacitances	p. 277
Gate Resistance	p. 280
Interconnect R and C	p. 283
Sensitivity of CMOS Delay to Device Parameters	p. 289
Propagation Delay and Delay Equation	p. 289
Delay Sensitivity to Channel Width, Length, and Gate Oxide Thickness	p. 296
Sensitivity of Delay to Power-supply Voltage and Threshold Voltage	p. 299
Sensitivity of Delay to Parasitic Resistance and Capacitance	p. 301
Delay of Two-Way NAND and Body Effect	p. 304
Performance Factors of Advanced CMOS Devices	p. 307
Mosfets in RF Circuits	p. 308
Effect of Transport Parameters on CMOS Performance	p. 311
Low-Temperature CMOS	p. 312
Exercises	p. 315
Bipolar Devices	p. 318
n-p-n Transistors	p. 318
Basic Operation of a Bipolar Transistor	p. 322
Modifying the Simple Diode Theory for Describing Bipolar Transistors	p. 322
Ideal Current-Voltage Characteristics	p. 327
Collector Current	p. 329
Base Current	p. 330
Current Gains	p. 334
Ideal Ic-VCE Characteristics	p. 336
Characteristics of a Typical n-p-n Transistor	p. 337
Effect of Emitter and Base Series Resistances	p. 338
Effect of Base-Collector Voltage on Collector Current	p. 340
Collector Current Falloff at High Currents	p. 343
Nonideal Base Current at Low Currents	p. 347
Bipolar Device Models for Circuit and Time-Dependent Analyses	p. 352
Basic de Model	p. 352
Basic ac Model	p. 355
Small-Signal Equivalent-Circuit Model	p. 356
Emitter Diffusion Capacitance	p. 359
Charge-Control Analysis	p. 361
Breakdown Voltages	p. 366
Common-Base Current Gain in the Presence of Base-Collector Junction Avalanche	p. 367
Saturation Currents in a Transistor	p. 369
Relation Between BV CEO and BV CBO	p. 370
Exercises	p. 371
Bipolar Device Design	p. 374
Design of the Emitter Region	p. 374
Diffused or Implanted-and-Diffused Emitter	p. 375
Polysilicon Emitter	p. 376
Design of the Base Region	p. 377
Relationship between Base Sheet Resistivity and Collector Current Density	p. 378
Intrinsic-Base Dopant Distribution	p. 380
Electric Field in the Quasineutral Intrinsic Base	p. 381
Base Transit Time	p. 384
Design of the Collector Region	p. 385
Collector Design When There is Negligible Base Widening	p. 387
Collector Design When There is Appreciable Base Widening	p. 388
SiGe-Base Bipolar Transistors	p. 389
Transistors Having a Simple Linearly Graded Base Bandgap	p. 390
Base Current When Ge Is Present in the Emitter	p. 396
Transistors Having a Trapezoidal Ge Distribution in the Base	p. 401
Transistors Having a Constant Ge Distribution in the Base	p. 406
Effect of Emitter Depth Variation on Device Characteristics	p. 410
Some Optimal Ge Profiles	p. 414
Base-Width Modulation by VBE	p. 419
Reverse-Mode I-V Characteristics	p. 423
Heterojunction Nature of a SiGe-Base Bipolar Transistor	p. 426
Modern Bipolar Transistor Structures	p. 429
Deep-Trench Isolation	p. 429
Polysilicon Emitter	p. 430
Self-Aligned Polysilicon Base Contact	p. 430
Pedestal Collector	p. 431
SiGe-Base	p. 431
Exercises	p. 432
Bipolar Performance Factors	p. 437
Figures of Merit of a Bipolar Transistor	p. 437
Cutoff Frequency	p. 437
Maximum Oscillation Frequency	p. 440
Ring Oscillator and Gate Delay	p. 440
Digital Bipolar Circuits	p. 441
Delay Components of a Logic Gate	p. 442
Device Structure and Layout for Digital Circuits	p. 445
Bipolar Device Optimization for Digital Circuits	p. 447
Design Points for a Digital Circuit	p. 447
Device Optimization When there is Significant Base Widening	p. 448
Device Optimization When There is Negligible Base Widening	p. 449
Device Optimization for Small Power-Delay Product	p. 453
Bipolar Device Optimization from Some Data Analyses	p. 455
Bipolar Device Scaling for ECL Circuits	p. 457
Device Scaling Rules	p. 458
Limits in Bipolar Device Scaling for ECL Circuits	p. 460
Bipolar Device Optimization and Scaling for RF and Analog Circuits	p. 463
The Single-Transistor Amplifier	p. 463
Optimizing the Individual Parameters	p. 464
Technology for RF and Analog Bipolar Devices	p. 467
Limits in Scaling Bipolar Transistors for RF and Analog Applications	p. 468
Comparing a SiGe-Base Bipolar Transistor with a GaAs HBT	p. 469
Exercises	p. 472
Memory Devices	p. 476
Static Random-Access Memory	p. 477
CMOS SRAM Cell	p. 478
Other Bistable MOSFET SRAM Cells	p. 486
Bipolar SRAM Cell	p. 487
Dynamic Random-Access Memory	p. 495
Basic DRAM Cell and Its Operation	p. 496
Device Design and Scaling Considerations for a DRAM Cell	p. 499
Nonvolatile Memory	p. 500
Mosfet Nonvolatile Memory Devices	p. 501
Flash Memory Arrays	p. 507
Floating-Gate Nonvolatile Memory Cells	p. 511
Nonvolatile Memory Cells with Charge Stored in Insulator	p. 514
Exercise	p. 516
Silicon-on-Insulator Devices	p. 517
SOI CMOS	p. 517
Partially Depleted SOI Mosfets	p. 518
Fully Depleted SOI Mosfets	p. 520
Thin-Silicon SOI Bipolar	p. 523
Fully Depleted Collector Mode	p. 524
Partially Depleted Collector Mode	p. 526
Accumulation Collector Mode	p. 527
Discussion	p. 527
Double-Gate Mosfets	p. 529
An Analytic Drain Current Model for Symmetric DG Mosfets	p. 529
The Scale Length of Double-Gate Mosfets	p. 533
Fabrication Requirements and Challenges of DG Mosfets	p. 534
Multiple-Gate Mosfets	p. 536
Exercise	p. 537
CMOS Process Flow	p. 538
Outline of a Process for Fabricating Modern n-p-n Bipolar Transistors	p. 542
Einstein Relations	p. 543
Spatial Variation of Quasi-Fermi Potentials	p. 546
Generation and Recombination Processes and Space-Charge-Region Current	p. 553
Diffusion Capacitance of a p-n Diode	p. 562
Image-Force-Induced Barrier Lowering	p. 569
Electron-Initiated and Hole-Initiated Avalanche Breakdown	p. 573
An Analytical Solution for the Short-Channel Effect in Subthreshold	p. 575
Generalized Mosfet Scale Length Model	p. 582
Drain Current Model of a Ballistic Mosfet	p. 588
Quantum-Mechanical Solution in Weak Inversion	p. 594
Power Gain of a Two-Port Network	p. 598
Unity-Gain Frequencies of a Mosfet Transistor	p. 601
Determination of Emitter and Base Series Resistances	p. 605
Intrinsic-Base Resistance	p. 610
Energy-Band Diagram of a Si-SiGe n-p Diode	p. 614
ftand fmax of a Bipolar Transistor	p. 617
References	p. 623
Index	p. 644
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