Ferroelectricity in Doped Hafnium Oxide: Materials, Properties and Devices (Woodhead Publishing Series in Electronic and Optical Materials)

Ferroelectricity in Doped Hafnium Oxide: Materials, Properties and Devices covers all aspects relating to the structural and electrical properties of HfO 2 and its implementation into semiconductor devices, including a comparison to standard ferroelectric materials. The ferroelectric and field-induced ferroelectric properties of HfO 2 -based films are considered promising for various applications, including non-volatile memories, negative capacitance field-effect-transistors, energy storage, harvesting, and solid-state cooling. Fundamentals of ferroelectric and piezoelectric properties, HfO 2 processes, and the impact of dopants on ferroelectric properties are also extensively discussed in the book, along with phase transition, switching kinetics, epitaxial growth, thickness scaling, and more. Additional chapters consider the modeling of ferroelectric phase transformation, structural characterization, and the differences and similarities between HFO 2 and standard ferroelectric materials. Finally, HfO 2 based devices are summarized. Explores all aspects of the structural and electrical properties of HfO 2 , including processes, modelling and implementation into semiconductor devices Considers potential applications including FeCaps, FeFETs, NCFETs, FTJs and more Provides comparison of an emerging ferroelectric material to conventional ferroelectric materials with insights to the problems of downscaling that conventional ferroelectrics face Front Cover......Page 1 Ferroelectricity in Doped Hafnium Oxide: Materials, Properties and Devices......Page 4 Copyright......Page 5 Contents......Page 6 Contributors......Page 14 Preface......Page 18 1.1. Piezoelectricity and Ferroelectricity......Page 20 1.2. Crystal Symmetry Considerations......Page 21 1.3. Thermodynamics......Page 22 1.4. Phonon Contributions to Ferroelectricity......Page 26 1.6. Ferroelectric Domains......Page 28 1.7. Scaling Effects......Page 31 1.8. Ferroelectric Fatigue......Page 34 1.9. Measurements and Artifacts......Page 36 References......Page 41 2.1. Structure of HfO2......Page 44 2.2. Temperature- and Pressure-Induced Phase Transformations......Page 47 2.4. Doping Effects of HfO2......Page 51 2.4.1. Isovalent Alloying: Zr4+ and Si4+......Page 52 2.4.2. Aliovalent Doping: Y, Gd, La, Sc, and Sr......Page 54 2.5. Dielectric Properties......Page 59 2.6. Conclusions......Page 60 References......Page 61 Chapter 3: Root Causes for Ferroelectricity in Doped HfO2......Page 66 3.1.1. Introduction......Page 68 3.1.2. Effect of Doping Concentration on Ferroelectric Doped HfO2......Page 69 3.1.3. Effect of Annealing Temperature on Ferroelectric Doped HfO2......Page 84 3.1.4. Conclusion......Page 88 References......Page 89 3.2.1. Introduction......Page 94 3.2.2. Effect of Film Composition and Thickness......Page 97 3.2.3. Effect of Deposition Temperature......Page 102 3.2.4.1. Annealing Atmosphere......Page 107 3.2.4.2. Annealing Temperature......Page 109 3.2.5. Conduction Mechanism......Page 111 3.2.6. Endurance......Page 113 3.2.7. Conclusion and Outlook......Page 115 References......Page 116 3.3.1. Introduction......Page 122 3.3.2. Ferroelectric Phase HfO2......Page 125 3.3.3. Experimental......Page 126 3.3.4.1. Ferroelectric Properties of Doped HfO2......Page 128 3.3.4.2. Effect of Size and Valence of Dopants......Page 131 3.3.4.3. A universal Driving Force Toward the Ferroelectric HfO2 Formation......Page 133 3.3.4.4. (Hf-Zr)O2 System......Page 136 3.3.5. Local Ferroelectric Phase Formation by Ion Implantation......Page 138 3.3.6. Conclusion......Page 142 References......Page 143 3.4.1. Introduction......Page 146 3.4.2.2. Precursor Solutions......Page 148 3.4.2.3. Thermal Analysis......Page 150 3.4.2.4. CSD Processing......Page 152 3.4.3.1. Effect of Dopants......Page 154 3.4.3.2. Processing Influence......Page 156 3.4.3.3. Thickness Dependence......Page 157 3.4.4. Conclusion......Page 159 References......Page 160 3.5.1. Introduction......Page 164 3.5.2. Effect of Film Thickness in ALD Films......Page 166 3.5.3. Interleaved Effects Complicating the Experimental Assessment......Page 170 3.5.4. Thickness Scalability of Physical Vapor-Deposited Ferroelectric HfO2 Layers......Page 174 3.5.5. Effect of Film Thickness in Chemical Solution-Deposited Films......Page 177 3.5.6. Stress and Strain......Page 180 3.5.7. Conclusion......Page 186 Acknowledgments......Page 187 References......Page 188 4.1. Introduction......Page 192 4.2. Epitaxial Growth of Orthorhombic HfO2 Films......Page 193 4.3. Effect of Orientations and Ferroelectric Properties......Page 199 4.4. Epitaxial Growth by Room Temperature Deposition and Annealing......Page 207 References......Page 209 5.1.1. First-Order Phase Transition in Fluorite Ferroelectrics......Page 212 5.1.2. Phase Transition in Epitaxial Y:HfO2 Thin Film......Page 215 5.1.3.1. Structural Origin of Temperature-Dependent Ferroelectricity......Page 219 5.1.3.2. Structural Evolution During the Annealing Process......Page 223 5.1.3.3. The Phase Transition in a Temperature Range From 110 to 1173K......Page 227 5.1.4. General Structural Evolution of Ferroelectric Doped HfO2 Thin Films During Annealing......Page 228 5.1.5. Conclusion......Page 231 References......Page 232 Further Reading......Page 235 5.2.1. Introduction......Page 236 5.2.2.1. Broad Phase Transition in Fluorite-Type Ferroelectrics......Page 239 5.2.2.2. Effect of Dopant Species on Ferroelectric HfO2 Thin Films......Page 242 5.2.3.1. Conventional Electrocaloric Effect......Page 245 5.2.3.2. Negative Electrocaloric Effect......Page 250 5.2.4. Pyroelectric Energy Harvesting......Page 253 5.2.5. Pyroelectric Coefficient and Infrared Sensing Application......Page 254 5.2.6. Perspectives......Page 256 Acknowledgments......Page 259 References......Page 260 6.1. Introduction......Page 264 6.1.1. Crystallographic Phases of HfO2......Page 266 6.1.2. Thermodynamic Model......Page 272 6.1.3. DFT: Advantages and Limitations......Page 273 6.2.1. Surface and Interface Energy......Page 275 6.2.2. Stress and Strain......Page 279 6.2.3. Electric Field......Page 281 6.2.4. Entropy......Page 283 6.2.5. Combination of Factors......Page 285 6.3. Chemical Factors: Point Defects in HfO2......Page 287 6.3.1. Oxygen Vacancies......Page 289 6.3.2. Defect Charge and Fermi Level......Page 291 6.3.3. Silicon and Other Isovalent Dopants......Page 292 6.3.4. Aliovalent Dopants......Page 295 6.3.5. Trends in Doping......Page 298 6.4. Conclusion and Outlook......Page 303 References......Page 304 7.1.1. Introduction......Page 310 7.1.2. PFM on Bare HfO2/ZrO2-Based Thin Films......Page 312 7.1.3. PFM on HfO2/ZrO2-Based Thin Film Capacitors......Page 315 7.1.4. Frequency-Independent (Nonresonant) PFM: A New Potential of the Classic Approach......Page 321 Acknowledgments......Page 328 References......Page 329 7.2.2. Early Studies......Page 336 7.2.3. Polymorphs of Hafnia......Page 337 7.2.4. Identifying the Ferroelectric Phase......Page 340 7.2.5. Evidence for Bulk Phase Changes and Interfacial Dielectric Layers......Page 343 7.2.6. Grain Structure and Grain Nonuniformity in Ferroelectric Hafnia......Page 347 7.2.7. Conclusions and Open Questions......Page 354 Acknowledgments......Page 355 References......Page 356 8.1. Introduction......Page 360 8.2.1. Effect of the Bottom Electrode......Page 362 8.2.2. Effect of the Top Electrode......Page 367 8.3. Comparison of TiN and TaN Electrodes......Page 370 8.4. Semiconductor Electrodes......Page 375 8.5. Conclusion and Outlook......Page 377 References......Page 379 9.1.2. Polarization Reversal in HfO2-Based Ferroelectrics......Page 384 9.1.3. Ferroelectric Switching at the Nanoscale......Page 385 9.1.4. Stochastic Switching......Page 391 9.1.5. Modeling of the Switching Behavior......Page 393 9.1.6. Discussion......Page 397 References......Page 398 9.2.1. Introduction......Page 400 9.2.2. Relation of Coercive and Breakdown Field......Page 402 9.2.3. Polarization Enhancement During Field Cycling......Page 403 9.2.4. Polarization Fatigue......Page 407 9.2.5. Retention Characteristics......Page 410 9.2.6. Summary......Page 411 References......Page 413 9.3.2. Models for Assessment of Dielectric and Ferroelectric Properties......Page 418 9.3.3. Ferroelectric Properties and Polarization Hysteresis Modeling Approaches......Page 421 9.3.4. Dielectric Degradation due to the Field Cycling of the Ferroelectric Storage Capacitor......Page 422 9.3.5. Simulation and Modeling of Wake-Up and Fatigue in Ferroelectric HfO2-Based Capacitors......Page 423 References......Page 428 Further Reading......Page 430 10.1.1. Introduction......Page 432 10.1.2. Ferroelectric Random Access Memory: Capacitor Integration......Page 433 10.1.3. Ferroelectric Random Access Memory Architectures and Operation......Page 434 10.1.4. Implications of Using HfO2-Based Ferroelectric Capacitors in FeRAM Memory Cells......Page 437 10.1.5. Scalability of the HfO2-Based Ferroelectric Capacitor......Page 441 References......Page 442 10.2.1. Doped HfO2 and ZrO2 for DRAM and FRAM Applications......Page 444 10.2.2. Theoretical Basics of Antiferroelectric Nonvolatile Memory......Page 445 10.2.3. Realization of Antiferroelectric Nonvolatile Memory......Page 447 10.2.4. Performance and Reliability of Antiferroelectric Capacitor......Page 449 10.2.5. Integration and Operation of an Antiferroelectric Capacitor for Nonvolatile Memory Applications......Page 451 References......Page 453 10.3.1. Introduction......Page 456 10.3.2. Ferroelectric HfO2-Based Tunnel Junction......Page 458 10.3.3. Depolarization Field in the HfO2 FTJ......Page 460 10.3.4. Tunneling Electroresistance of the HfO2 FTJ: A Theoretical Approach......Page 462 10.3.5. Summary......Page 465 References......Page 466 10.4.2. Basic Working Principle......Page 470 10.4.3. Scaling and Variability at the Nanoscale......Page 476 10.4.4. Retention Limitations......Page 477 10.4.5. Endurance Limitations......Page 479 10.4.5.1. Tailoring the Ferroelectric Polarization......Page 482 10.4.5.2. Utilizing Subloop Operation......Page 483 10.4.5.3. Tailoring the Capacitive Divider......Page 484 References......Page 488 Further Reading......Page 490 10.5.1. Introduction......Page 492 10.5.2. Disambiguation of Negative Capacitance Effects......Page 494 10.5.3.1. Transient Negative Capacitance in HfO2-Based Capacitors......Page 495 10.5.3.2.1. Role of the Internal Metal Gate in NCFETs......Page 499 10.5.3.2.2. HfO2-Based NCFET Publications Until 2015......Page 500 10.5.3.2.3. HfO2-Based NCFET Publications in 2016......Page 502 10.5.3.2.4. HfO2-Based NCFET Publications From 2017 and Later......Page 503 10.5.4. Conclusion and Outlook......Page 507 References......Page 508 10.6.1. Introduction......Page 514 10.6.2. Introduction to Ferroelectric Logic-in-Memory Concepts......Page 516 10.6.2.1. Concept Class 1: Ferroelectric Element Serves as an Input......Page 517 10.6.2.2. Concept Class 2: Ferroelectric Element for the Storage of Logical Outputs......Page 526 10.6.2.3. Concept Class 3: The Ferroelectric Element Improves Other Characteristics......Page 528 10.6.3. Summary......Page 529 References......Page 530 10.7.1. Introduction......Page 534 10.7.2. Gradual Switching......Page 535 10.7.3. Ferroelectric Synapse......Page 539 10.7.4. Synaptic Plasticity......Page 540 10.7.5. Spike Transmission......Page 542 10.7.6. Discussion......Page 543 References......Page 544 Nomenclature......Page 548 Acronyms......Page 554 Index......Page 560 Back Cover......Page 572 __Ferroelectricity in Doped Hafnium Oxide: Materials, Properties and Devices__Additional chapters consider the modeling of ferroelectric phase transformation, structural characterization, and the differences and similarities between HFO2 and standard ferroelectric materials. Finally, HfO2 based devices are summarized.