Ferroelectricity in Doped Hafnium Oxide: Materials, Properties and Devices covers all aspects relating to the structural and electrical properties of HfO2 and its implementation into semiconductor devices, including a comparison to standard ferroelectric materials. The ferroelectric and field-induced ferroelectric properties of HfO2-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, HfO2 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 HFO2 and standard ferroelectric materials. Finally, HfO2 based devices are summarized. Explores all aspects of the structural and electrical properties of HfO2, 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

In 2011, Böscke et al. reported the unexpected discovery of ferroelectric properties in hafnia based thin films, which has since initiated many further studies and revitalized research on the topic of ferroelectric memories. In spite of many efforts, the unveiling of the fundamentals behind this surprising discovery has proven rather challenging. In this work, the originally claimed Pca21 phase is experimentally proven to be the root of the ferroelectric properties and the nature of this ferroelectricity is classified in the frame of existing concepts of ferroelectric materials. Parameters to stabilize this polar phase are examined from a theoretical and fabrication point of view. With these very basic questions addressed, the application relevant electric field cycling behavior is studied. The results of first-order reversal curves, impedance spectroscopy, scanning transmission electron microscopy and piezoresponse force microscopy significantly advance the understanding of structural mechanisms underlying wake-up, fatigue and the novel phenomenon of split-up/merging of transient current peaks. The impact of field cycling behavior on applications like ferroelectric memories is highlighted and routes to optimize it are derived. These findings help to pave the road for a successful commercialization of hafnia based ferroelectrics.

This is a standard work on ferroelectrics.

Edited by major contributors to the field, this text summarizes current or newly emerging pulsed laser deposition application areas. It spans the field of optical devices, electronic materials, sensors and actuators, biomaterials, and organic polymers. Every scientist, technologist and development engineer who has a need to grow and pattern, to apply and use thin film materials will regard this book as a must-have resource.

This dissertation investigates the phenomenon of negative capacitance in ferroelectric materials, which is promising for overcoming the fundamental limits of energy efficiency in electronics. The focus of this dissertation is on negative capacitance in hafnium oxide based ferroelectrics and the impact of ferroelectric domain formation.

This book provides comprehensive coverage of the materials characteristics, process technologies, and device operations for memory field-effect transistors employing inorganic or organic ferroelectric thin films. This transistor-type ferroelectric memory has interesting fundamental device physics and potentially large industrial impact. Among various applications of ferroelectric thin films, the development of nonvolatile ferroelectric random access memory (FeRAM) has been most actively progressed since the late 1980s and reached modest mass production for specific application since 1995. There are two types of memory cells in ferroelectric nonvolatile memories. One is the capacitor-type FeRAM and the other is the field-effect transistor (FET)-type FeRAM. Although the FET-type FeRAM claims the ultimate scalability and nondestructive readout characteristics, the capacitor-type FeRAMs have been the main interest for the major semiconductor memory companies, because the ferroelectric FET has fatal handicaps of cross-talk for random accessibility and short retention time. This book aims to provide the readers with development history, technical issues, fabrication methodologies, and promising applications of FET-type ferroelectric memory devices, presenting a comprehensive review of past, present, and future technologies. The topics discussed will lead to further advances in large-area electronics implemented on glass, plastic or paper substrates as well as in conventional Si electronics. The book is composed of chapters written by leading researchers in ferroelectric materials and related device technologies, including oxide and organic ferroelectric thin films.

This work investigates the crystallography and dielectric properties of Zirconium- and Hafnium-oxide based nano-scale thin film insulators for memory. Hafnium- and Zirconium-oxide are industry leading candidates for high-k dielectrics. Most application research has focused on the application of amorphous high-k due to formation of defects associated with the crystalline phase. However the application of crystalline dielectrics offers two advantages: Potentially high thermal stability, since no measures have to be taken to avoid crystallization, and the ability to manipulate crystalline phase composition to maximize dielectric constants. Pure ZrO2 crystallized at a lower temperature than HfO2 and always formed a metastable t’ higher-k phase. ZrO2 crystallized already during deposition, leading to leakage current degradation. It was shown that this problem could be solved by SiO2 addition to raise the crystallization temperature, allowing fabrication of low leakage, low effective oxide thickness (EOT) metal-insulator-metal (MIM) capacitors suitable for stack based DRAM down to the 4X nm node. HfO2, in contrast, formed a mixture of monoclinic and tetragonal phase which led to the formation of mechanical defects (microcracks). Addition of SiO2 allowed manipulating the phase composition of HfO2. When up to 7 mol% SiO2 was added, increased stabilization of the metastable t' phase with a dielectric constant of 34-36 was observed. It could be shown that the stabilization is due to a combination of a surface energy effect and solved SiO2 in the HfO2 lattice. Above 11 mol% SiO2 segregated from HfO2 and a tetragonal phase with higher c/a splitting and lower dielectric constant was stabilized instead. It was discovered that the behavior of HfSiO was fundamentally altered if it was crystallized under mechanical confinement in presence of a top electrode. Besides a significant increase in dielectric constant, the material exhibited ferroelectric and antiferroelectric polarization hysteresis, a characteristic not previously reported for HfO2 or ZrO2. This behavior originated from the formation of a new orthorhombic crystal phase. Utilizing the increased permittivity of the antiferroelectic phase, it was possible to demonstrate low EOT, highly temperature stable, MIM capacitors with potential application in sub 50 nm deep trench-DRAM generations. Novel ferroelectric HfSiO was used to fabricate ferroelectric field effect transistors which allowed long term nonvolatile data storage. The electrical characteristics of the devices meet or exceed that of the best published literature results. Full compatibility to silicon semiconductor technology with a gate stack thickness down to 5 nm was demonstrated for the first time, suggesting that HfSiO based FEFETs can potentially be scaled to below the 30 nm node. This goal could not be achieved with previously known materials.