Principles of Semiconductor Devices

The dimensions of modern semiconductor devices are reduced to the point where the classical semiconductor theory, including the concepts of continuous particle concentration and continuous current, becomes questionable. Further questions relate to the two-dimensional transport in the most important field-effect devices and the one-dimensional transport in nanowires and carbon nanotubes. Designed for upper-level undergraduate and graduate courses,Principles of Semiconductor Devices, Second Edition, presents the semiconductor-physics and device principles in a way that upgrades the classical semiconductor theory and enables proper interpretations of numerous quantum effects in modern devices. The semiconductor theory is directly linked to practical applications, including the links to SPICE models and parameters that are commonly used during circuit design. The text is divided into three parts: Part I explains semiconductor physics; Part II presents the principles of operation and modeling of the fundamental junctions and transistors; and Part III provides supplementary topics, including a dedicated chapter on the physics of nanoscale devices, description of SPICE models and equivalent circuits that are needed for circuit design, introductions to most important specific devices (photonic devices, JFETs and MESFETs, negative-resistance diodes, and power devices), and an overview of integrated-circuit technologies. The chapters and the sections in each chapter are organized so to enable instructors to select more rigorous and design-related topics as they see fit. New to this Edition * A new chapter on the physics of nanoscale devices * A revised chapter on the energy-band model and fully reworked and updated material on crystals to include graphene and carbon nanotubes * A revised P-N junction chapter to emphasize the current mechanisms that are relevant to modern devices * JFETs and MESFETs in a stand-alone chapter * Fifty-seven new problems and eleven new examples

Sima Dimitrijev is Professor at the Griffith School of Engineering and Deputy Director of Queensland Micro- and Nanotechnology Centre at Griffith University in Australia. He is the author of Understanding Semiconductor Devices (OUP, 2000) as well as numerous other publications in the areas of MOSFET technology, modeling, and applications.

Contents
PART I INTRODUCTION TO SEMICONDUCTORS
1 lNTRODUCTION TO CRYSTALS AND CURRENT CARRIERS
IN SEMICONDUCTORS, THE ATOMIC-BOND MODEL
1.1 INTRODUCTION TO CRYSTALS
1.1.1 Atomic Bonds
1.1.2 Three-Dimensional Crystals
1.1.3 Two-Dimensional Crystals: Graphene and Carbon Nanotubes
1.2 CURRENT CARRIERS
1.2.1 Two Types of Current Carriers in Semiconductors
1.2.2 N·Type and P-Type Doping
1.2.3 Electroneutrality Equation
1.2.4 Electron and Hole Generation and Recombination in Thermal Equilibrium
1.3 BASICS OF CRYSTAL GROWTH AND DOPING TECHNIQUES
1.3.1 Crystal-Growth Techniques
1.3.2 Doping Techniques
Summary
Problems
Review Questions

2 THE ENERGY-BAND MODEL
12.1 ELECTRONS AS WAVES
2.1.1 De Broglie Relationship Between Particle and Wave Properties
2.1.2 Wave Function and Wave Packet
2.1.3 Schrodinger Equation
2.2 ENERGY LEVELS IN ATOMS AND ENERGY BANDS IN CRYSTALS
2.2.1 Atomic Structure
2.2.2 Energy Bands in Metals
2.2.3 Energy Gap and Energy Bands in Semiconductors and Insulators
12.3 ELECTRONS AND HOLES AS PARTICLES
2.3.1 Effective Mass and Real E-k Diagrams
2.3.2 The Question of Electron Size: The Uncertainty Principle
2.3.3 Density of Electron States
2.4 POPULATION OF ELECTRON STATES, CONCENTRATIONS OF
ELECTRONS A:"D HOLES
2.4.1 Fermi-Dirac Distribution
2.4.2 Maxwell-Boltzmann Approximation and Effective Density of States
2.4.3 Fermi Potential and Doping
2.4.4 Nonequilibrium Carrier Concentrations and Quasi-Fermi Levels
Summary
Problems
Review Questions

3 DRIFT
3.1 ENERGY BANDS WITH APPLIED ELECTRIC FIELD
3.1.1 Energy-Band Presentation of Drift Current
3.1.2 Resistance and Power Dissipation due to Carrier Scattering
3.2 OHM'S LAW, SHEET RESISTANCE, AND CONDUCTIVITY
3.2.1 Designing Integrated-Circuit Resistors
3.2.2 Differential Form of Ohm's Law
3.2.3 Conductivity Ingredients
3.3 CARRIER MOBILITY
3.3.1 Thermal and Drift Velocities
3.3.2 Mobility Definition
3.3.3 Scattering Time and Scattering Cross Section
3.3.4 Mathieson's Rule
°3.3.5 Hall Effect
Summary
Problems
Review Questions

4 DlFFUSION
4.1 DIFFUSION-CURRENT EQUATION
4.2 DIFFUSION COEFFICIENT
4.2.1 Einstein Relationship


·4.2.2 Haynes-Shockley Experiment
4.2.3 Arrhenius Equation
4.3 BASIC CONTINUITY EQUATION
Summary
Problems
Review Questions

5 GENERATION AND RECOMBINATION
5.1 GENERATION AND RECOMBINATION MECHANISMS
5.2 GENERAL FORM OF THE CONTINUITY EQUATION
5.2.1 Recombination and Generation Rates
5.2.2 Minority-Carrier Lifetime
5.2.3 Diffusion Length
5.3 GENERATION AND RECOMBINATION PHYSICS AND SHOCKLEYREAD-
HALL (SRH) THEORY
5.3.1 Capture and Emission Rates in Thermal Equilibrium
5.3.2 Steady-State Equation for the Effective Thermal Generation/Recombination
Rate
5.3.3 Special Cases
5.3.4 Surface Generation and Recombination
Summary
Problems
Review Questions

PART II FUNDAMENTAL DEVICE STRUCTURES
6 P-N JUNCTION
6.1 P-N JUNCTION PRINCIPLES
6.1.1 p-~ Junction in Thermal Equilibrium
6.1.2 Reverse-Biased P-N Junction
6.1.3 Forward-Biased P-K Junction
6.1.4 Breakdown Phenomena
6.2 DC MODEL
6.2.1 Basic Current-Voltage (I-V) Equation
6.2.2 Important Second-Order Effects
6.2.3 Temperature Effects
6.3 CAPACITA CE OF REVERSE-BIASED P-:-I JUNCTION
6.3.1 C-V Dependence
6.3.2 Depletion-Layer Width: Solving the Poisson Equation
6.3.3 SPICE Model for the Depletion-Layer Capacitance
6.4 STORED-CHARGE EFFECTS
6.4.1 Stored Charge and Transit Time
6.4.2 Relationship Between the Transit Time and the Minority-Carrier
Lifetime
6.4.3 Switching Characteristics: Reverse-Recovery Time
Summary
Problems
Review Questions

7 METAL-SEMICONDUCTOR CONTACT AND MOS CAPACITOR
7.1 METAL-SEMICONDUCTOR CONTACT
7.1.1 Schottky Diode: Rectifying Metal-Semiconductor Contact
7.1.2 Ohmic Metal-Semiconductor Contacts
7.2 MOS CAPACITOR
7.2.1 Properties of the Gate Oxide and the Oxide-Semiconductor Interface
7.2.2 C-V Curve and the Surface-Potential Dependence on Gate Voltage
7.2.3 Energy-Band Diagrams
·7.2.4 Flat4Band Capacitance and Debye Length
Summary
Problems
Review Questions

8 MOSFET
8.1 MOSFET PRINCIPLES
B.1.1 MOSFET Structure
8.1.2 MOSFET as a Voltage-Controlled Switch
B.1.3 The Threshold Voltage and the Body Effect
B.1.4 MOSFET as a Voltage-Controlled Current Source: Mechanisms of
Current Saturation
8.2 PRINCIPAL CURRENT-VOLTAGE CHARACTERISTICS AND EQUATIONS
8.2.1 SPICE LEVEL 1 Model
8.2.2 SPICE LEVEL 2 Model
8.2.3 SPICE LEVEL 3 Model: Principal Effects
8.3 SECO:\D-OROER EFFECTS
8.3.1 Mobility Reduction with Gate Voltage
8.3.2 Velocity Saturation (Mobility Reduction with Drain Voltage)
8.3.3 Finite Output Resistance
8.3.4 Threshold-Voltage-Related Short-Channel Effects
8.3.5 Threshold Voltage Related Narrow-Channel Effects
8.3.6 Subthreshold Current
8.4 Nanoscale MOSFETs
8.4.1 Down-Scaling Benefits and Rules
8.4.2 Leakage Currents
8.4.3 Advanced MOSFETs
"8.5 MOS-BASED MEMORY DEVICES
8.5.1 1C1T DRAM Cell
8.5.2 Flash-Memory Cell
Summary
Problems
Review Questions

9 BJT
9.1 B.JT PRINCIPLES
9.1.1 BJT as a Voltage-Controlled Current Source
9.1.2 BJT Currents and Gain Definitions
9.1.3 Dependence of ? and ? Current Gains on Technological Parameters
9.1.4 The Four Modes of Operation: BJT as a Switch
9.1.5 Complementary BJT
9.1.6 BJT Versus MOSFET
9.2 PRINCIPAL CURRENT-VOLTAGE CHARACTERISTICS, EBERE-MOLL
MODEL IN SPICE
9.2.1 Injection Version
9.2.2 Transport Version
9.2.3 SPICE Version
9.3 SECOND·ORDER EFFECTS
9.3.1 Early Effect: Finite Dynamic Output Resistance
9.3.2 Parasitic Resistances
9.3.3 Dependence of Common-Emitter Current Gain on Transistor Current:
Low-Current Effects
9.3.4 Dependence of Common-Emitter Current Gain on Transistor Current:
Gummel-Poon Model for High-Current Effects
9.4 HETEROJUNCTION BIPOLAR TRANSISTOR
Summary
Problems
Review Questions

PART III SUPPLEMENTARY TOPICS
10 PHYSICS OF NANOSCALE DEVICES
10.1 SINGLE-CARRIER EVENTS
10.1.1 Beyond the Classical Principle of Continuity
10.1.2 Current-Time Form of Uncertainty Principle
10.1.3 Carrier-Supply Limit to Diffusion Current
10.1.4 Spatial Uncertainty
10.1.5 Direct Nonequilibrium Modeling of Single-Carrier Events
10.2 TWO-DIMENSIONAL TRANSPORT IN MOSFETs AND HEMTs
10.2.1 Quantum Confinement
10.2.2 HEMT Structure and Characteristics
10.2.3 Application of Classical MOSFET Equations to Two-Dimensional
Transport in MOSFETs and HEMTs
10.3 ONE-DIMENSUIONAL TRANSPORT IN NANOWIRES AND CARBON
NANOTUBES
10.3.1 Ohmic Transport in Nanowire and Carbon-Nanotube FETs
10.3.2 One-Dimensional Ballistic Transport and the Quantum Conductance
Limit
Summary
Problems
Review Questions

II DEVICE ELECTRONICS, EQUIVALENT CIRCUITS A D SPICE
PARAMETERS
lI.l DIODES
11.1.1 Static Model and Parameters in SPICE
11.1.2 Large-Signal Equivalent Circuit in SPICE
11.1.3 Parameter Measurement
11.1.4 Small-Signal Equivalent Circuit
ll.2 MOSFET
11.2.1 Static Model and Parameters; LEVEL 3 in SPICE
11.2.2 Parameter Measurement
11.2.3 Large-Signal Equivalent Circuit and Dynamic Parameters in SPICE
11.2.4 Simple Digital ~1od.el
11.2.5 Small-Signal Equivalent Circuit
11.3 BJT
11.3.1 Static Model and Parameters: Ebers-Moll and Gummel-Poon Levels
in SPICE
11.3.2 Parameter Measurement
11.3.3 Large-Signal Equivalent Circuit and Dynamic Parameters in SPICE
11.3.4 Small-Signal Equivalent Circuit
Summary
Problems
Review Questions

12 PHOTONIC DEVICES
12.1 LIGHT EMITTING DIODES (LED)
12.2 PHOTODETECTORS AND SOLAR CELLS
12.2.1 Biasing for Photodetector and Solar-Cell Applications
12.2.2 Carrier Generation in Photodetectors and Solar Cells
12.2.3 Photocurrent Equation
12.3 LASERS
12.3.1 Stimulated Emission, Inversion Population, and Other Fundamental Concepts
12.3.2 A Typical Heterojunction Laser
Summary
Problems
Review Questions

13 JFET AND MESFET
13.1 JFET
13.1.1 JFET Structure
13.1.2 JFET Characteristics
13.1.3 SPICE Model and Parameters
13.2 MESFET
13.2.1 MESFET Structure
13.2.2 MESFET Characteristics
13.2.3 SPICE Model and Parameters
Summary
Problems
Review Questions

14 POWER DEVICES
14.1 POWER DIODES
14.1.1 Drift Region in Power Devices
14.1.2 Switching Characteristics
14.1.3 Schottky Diode
14.2 POWER MOSFET
14.3 IGBT
14.4 THYRISTOR
Summary
Problems
Review Questions

15 NEGATIVE RESISTANCE DIODES
15.1 AMPLIFICATION AI'D OSCILLATION BY NEGATIVE DYNAMIC
RESISTANCE
15.2 GUNN DIODE
15.3 IMPATT DIODE
15.4 TUNNEL DIODE
Summary
Problems
Review Questions

16 INTEGRATED-CIRCUIT TECHNOLOGIES
16.1 A DIODE IN IC TECHNOLOGY
16.1.1 Basic Structure
16.1.2 Lithography
16.1.3 Process Sequence
16.1.4 Diffusion Profiles
16.2 MOSFET TECHNOLOGIES
16.2.1 Local Oxidation of Silicon (LOCOS)
16.2.2 NMOS Technology
16.2.3 Basic CMOS Technology
16.2.4 Silicon-on-Insulator (SOl) Technology
16.3 BIPOLAR IC TECHNOLOGIES
16.3.1 IC Structure of NPN BJT
16.3.2 Standard Bipolar Technology Process
16.3.3 Implementation of PNP BJTs, Resistors, Capacitors, and Diodes
16.3.4 Parasitic IC Elements not Included in Device Models
16.3.5 Layer Merging
16.3.6 BiCMOS Technology
Summary
Problems
Review Questions