Sima Dimitrijev

Bio: Sima Dimitrijev is an academic researcher from Griffith University. The author has contributed to research in topics: Gate oxide & Silicon. The author has an hindex of 38, co-authored 284 publications receiving 5435 citations. Previous affiliations of Sima Dimitrijev include University of Niš.

Principles of semiconductor devices

Abstract: 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 L4.2.2 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 JUNCTIONS 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 6.5 METAL-SEMICONDUCTOR CONTACT 6.5.1 Schottky Diode: Rectifying Metal-Semiconductor Contact 6.5.2 Ohmic Metal-Semiconductor Contacts Summary Problems Review Questions 7 MOSFET 7.1 MOS CAPACITOR 7.1.1 Properties of the Gate Oxide and the Oxide-Semiconductor Interface 7.1.2 C-V Curve and the Surface-Potential Dependence on Gate Voltage 7.1.3 Energy-Band Diagrams 7.1.4 Flat4Band Capacitance and Debye Length 7.2 MOSFET PRINCIPLES B.1.1 MOSFET Structure 7.2.2 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 7.3 PRINCIPAL CURRENT-VOLTAGE CHARACTERISTICS AND EQUATIONS 7.3.1 SPICE LEVEL 1 Model 7.3.2 SPICE LEVEL 2 Model 7.3.3 SPICE LEVEL 3 Model: Principal Effects 7.4 SECO:\D-OROER EFFECTS 7.4.1 Mobility Reduction with Gate Voltage 7.4.2 Velocity Saturation (Mobility Reduction with Drain Voltage) 7.4.3 Finite Output Resistance 7.4.4 Threshold-Voltage-Related Short-Channel Effects 7.4.5 Threshold Voltage Related Narrow-Channel Effects 7.4.6 Subthreshold Current 7.5 Nanoscale MOSFETs 7.5.1 Down-Scaling Benefits and Rules 7.5.2 Leakage Currents 7.5.3 Advanced MOSFETs 7.6 MOS-BASED MEMORY DEVICES 7.6.1 1C1T DRAM Cell 7.6.2 Flash-Memory Cell Summary Problems Review Questions 8 BJT 8.1 B.JT PRINCIPLES 8.1.1 BJT as a Voltage-Controlled Current Source 8.1.2 BJT Currents and Gain Definitions 8.1.3 Dependence of ? and ? Current Gains on Technological Parameters 8.1.4 The Four Modes of Operation: BJT as a Switch 8.1.5 Complementary BJT 8.1.6 BJT Versus MOSFET 8.2 PRINCIPAL CURRENT-VOLTAGE CHARACTERISTICS, EBERE-MOLL MODEL IN SPICE 8.2.1 Injection Version 8.2.2 Transport Version 8.2.3 SPICE Version 8.3 SECOND*ORDER EFFECTS 8.3.1 Early Effect: Finite Dynamic Output Resistance 8.3.2 Parasitic Resistances 8.3.3 Dependence of Common-Emitter Current Gain on Transistor Current: Low-Current Effects 8.3.4 Dependence of Common-Emitter Current Gain on Transistor Current: Gummel-Poon Model for High-Current Effects 8.4 HETEROJUNCTION BIPOLAR TRANSISTOR Summary Problems Review Questions PART III SUPPLEMENTARY TOPICS 9 PHYSICS OF NANOSCALE DEVICES 9.1 SINGLE-CARRIER EVENTS 9.1.1 Beyond the Classical Principle of Continuity 9.1.2 Current-Time Form of Uncertainty Principle 9.1.3 Carrier-Supply Limit to Diffusion Current 9.1.4 Spatial Uncertainty 9.1.5 Direct Nonequilibrium Modeling of Single-Carrier Events 9.2 TWO-DIMENSIONAL TRANSPORT IN MOSFETs AND HEMTs 9.2.1 Quantum Confinement 9.2.2 HEMT Structure and Characteristics 9.2.3 Application of Classical MOSFET Equations to Two-Dimensional Transport in MOSFETs and HEMTs 9.3 ONE-DIMENSUIONAL TRANSPORT IN NANOWIRES AND CARBON NANOTUBES 9.3.1 Ohmic Transport in Nanowire and Carbon-Nanotube FETs 9.3.2 One-Dimensional Ballistic Transport and the Quantum Conductance Limit Summary Problems Review Questions 10 DEVICE ELECTRONICS, EQUIVALENT CIRCUITS A D SPICE PARAMETERS 10.l DIODES 10.1.1 Static Model and Parameters in SPICE 10.1.2 Large-Signal Equivalent Circuit in SPICE 10.1.3 Parameter Measurement 10.1.4 Small-Signal Equivalent Circuit 10.2 MOSFET 10.2.1 Static Model and Parameters LEVEL 3 in SPICE 10.2.2 Parameter Measurement 10.2.3 Large-Signal Equivalent Circuit and Dynamic Parameters in SPICE 10.2.4 Simple Digital ~1od.el 10.2.5 Small-Signal Equivalent Circuit 10.3 BJT 10.3.1 Static Model and Parameters: Ebers-Moll and Gummel-Poon Levels in SPICE 10.3.2 Parameter Measurement 10.3.3 Large-Signal Equivalent Circuit and Dynamic Parameters in SPICE 10.3.4 Small-Signal Equivalent Circuit Summary Problems Review Questions 11 PHOTONIC DEVICES 11.1 LIGHT EMITTING DIODES (LED) 11.2 PHOTODETECTORS AND SOLAR CELLS 11.2.1 Biasing for Photodetector and Solar-Cell Applications 11.2.2 Carrier Generation in Photodetectors and Solar Cells 11.2.3 Photocurrent Equation 11.3 LASERS 11.3.1 Stimulated Emission, Inversion Population, and Other Fundamental Concepts 11.3.2 A Typical Heterojunction Laser Summary Problems Review Questions 12 JFET AND MESFET 12.1 JFET 12.1.1 JFET Structure 12.1.2 JFET Characteristics 12.1.3 SPICE Model and Parameters 12.2 MESFET 12.2.1 MESFET Structure 12.2.2 MESFET Characteristics 12.2.3 SPICE Model and Parameters Summary Problems Review Questions 13 POWER DEVICES 13.1 POWER DIODES 13.1.1 Drift Region in Power Devices 13.1.2 Switching Characteristics 13.1.3 Schottky Diode 13.2 POWER MOSFET 13.3 IGBT 13.4 THYRISTOR Summary Problems Review Questions

Interfacial characteristics of n2o and no nitrided sio2 grown on sic by rapid thermal processing

Abstract: Interfacial characteristics of Al/SiO2/n-type 6H–SiC metal–oxide–semiconductor capacitors fabricated by rapid thermal processing (RTP) with N2O and NO annealing are investigated. Interface state density was measured by a conductance technique at room temperature. RTP oxidation in pure O2 leads to an excellent SiO2/n-type 6H–SiC interface with interface state density in the order of 1010–1011 eV−1 cm−2. NO annealing improves the SiO2/n-type 6H–SiC interface, while N2O annealing increases the interface state density.

Effects of nitridation in gate oxides grown on 4H-SiC

Abstract: Experiments have demonstrated that nitridation provides critically important improvements in the quality of SiO2–SiC interface. This article provides results and analysis aimed at developing the much needed understanding of the mechanisms and effects associated with both annealing of pregrown oxides and direct growth in NO and N2O environments. According to the model proposed in the article, nitridation plays a double role: (1) creation of strong Si≡N bonds that passivate interface traps due to dangling and strained bonds, and (2) removal of carbon and associated complex silicon–oxycarbon bonds from the interface. This understanding of the effects of nitridation is experimentally verified and used to design a superior process for gate oxide growth in the industry-preferred N2O environment.

The Piezoresistive Effect of SiC for MEMS Sensors at High Temperatures: A Review

Abstract: Silicon carbide (SiC) is one of the most promising materials for applications in harsh environments thanks to its excellent electrical, mechanical, and chemical properties. The piezoresistive effect of SiC has recently attracted a great deal of interest for sensing devices in hostile conditions. This paper reviews the piezoresistive effect of SiC for mechanical sensors used at elevated temperatures. We present experimental results of the gauge factors obtained for various poly-types of SiC films and SiC nanowires, the related theoretical analysis, and an overview on the development of SiC piezoresistive transducers. The review also discusses the current issues and the potential applications of the piezoresistive effect in SiC. [2015-0092]

Mechanisms responsible for improvement of 4H-SiC/SiO2 interface properties by nitridation

Abstract: An analysis of fast and slow traps at the interface of 4H–SiC with oxides grown in O2, N2O, and NO reveals that the dominant positive effect of nitridation is due to a significant reduction of the slow electron trap density. These traps are likely to be related to defects located in the near-interfacial oxide layer. In addition, the analysis confirms that the fast interface states related to clustered carbon are also reduced by nitridation.

When is nearest neighbor meaningful

Abstract: We explore the effect of dimensionality on the nearest neighbor problem. We show that under a broad set of conditions (much broader than independent and identically distributed dimensions), as dimensionality increases, the distance to the nearest data point approaches the distance to the farthest data point. To provide a practical perspective, we present empirical results on both real and synthetic data sets that demonstrate that this effect can occur for as few as 10-15 dimensions. These results should not be interpreted to mean that high-dimensional indexing is never meaningful; we illustrate this point by identifying some high-dimensional workloads for which this effect does not occur. However, our results do emphasize that the methodology used almost universally in the database literature to evaluate high-dimensional indexing techniques is flawed, and should be modified. In particular, most such techniques proposed in the literature are not evaluated versus simple linear scan, and are evaluated over workloads for which nearest neighbor is not meaningful. Often, even the reported experiments, when analyzed carefully, show that linear scan would outperform the techniques being proposed on the workloads studied in high (10-15) dimensionality!.

Piezoelectric and ferroelectric materials and structures for energy harvesting applications

Abstract: This review provides a detailed overview of the energy harvesting technologies associated with piezoelectric materials along with the closely related sub-classes of pyroelectrics and ferroelectrics. These properties are, in many cases, present in the same material, providing the intriguing prospect of a material that can harvest energy from multiple sources including vibration, thermal fluctuations and light. Piezoelectric materials are initially discussed in the context of harvesting mechanical energy from vibrations using inertial energy harvesting, which relies on the resistance of a mass to acceleration, and kinematic energy harvesting which directly couples the energy harvester to the relative movement of different parts of a source. Issues related to mode of operation, loss mechanisms and using non-linearity to enhance the operating frequency range are described along with the potential materials that could be employed for harvesting vibrations at elevated temperatures. In addition to inorganic piezoelectric materials, compliant piezoelectric materials are also discussed. Piezoelectric energy harvesting devices are complex multi-physics systems requiring advanced methodologies to maximise their performance. The research effort to develop optimisation methods for complex piezoelectric energy harvesters is then reviewed. The use of ferroelectric or multi-ferroic materials to convert light into chemical or electrical energy is then described in applications where the internal electric field can prevent electron–hole recombination or enhance chemical reactions at the ferroelectric surface. Finally, pyroelectric harvesting generates power from temperature fluctuations and this review covers the modes of pyroelectric harvesting such as simple resistive loading and Olsen cycles. Nano-scale pyroelectric systems and novel micro-electro-mechanical-systems designed to increase the operating frequency are discussed.

High-temperature electronics - a role for wide bandgap semiconductors?

Abstract: The fact that wide bandgap semiconductors are capable of electronic functionality at much higher temperatures than silicon has partially fueled their development, particularly in the case of SiC. It appears unlikely that wide bandgap semiconductor devices will find much use in low-power transistor applications until the ambient temperature exceeds approximately 300/spl deg/C, as commercially available silicon and silicon-on-insulator technologies are already satisfying requirements for digital and analog VLSI in this temperature range. However practical operation of silicon power devices at ambient temperatures above 200/spl deg/C appears problematic, as self-heating at higher power levels results in high internal junction temperatures and leakages. Thus, most electronic subsystems that simultaneously require high-temperature and high-power operation will necessarily be realized using wide bandgap devices, once they become widely available. Technological challenges impeding the realization of beneficial wide bandgap high ambient temperature electronics, including material growth, contacts, and packaging, are briefly discussed.

Material science and device physics in SiC technology for high-voltage power devices

Abstract: Power semiconductor devices are key components in power conversion systems. Silicon carbide (SiC) has received increasing attention as a wide-bandgap semiconductor suitable for high-voltage and low-loss power devices. Through recent progress in the crystal growth and process technology of SiC, the production of medium-voltage (600?1700 V) SiC Schottky barrier diodes (SBDs) and power metal?oxide?semiconductor field-effect transistors (MOSFETs) has started. However, basic understanding of the material properties, defect electronics, and the reliability of SiC devices is still poor. In this review paper, the features and present status of SiC power devices are briefly described. Then, several important aspects of the material science and device physics of SiC, such as impurity doping, extended and point defects, and the impact of such defects on device performance and reliability, are reviewed. Fundamental issues regarding SiC SBDs and power MOSFETs are also discussed.