A perspective on the physical scaling down of hafnia-based ferroelectrics

Abstract

HfO2-based ferroelectric thin films have attracted significant interest for semiconductor device applications due to their compatibility with complementary metal oxide semiconductor (CMOS) technology. One of the benefits of HfO2 based ferroelectric thin films is their ability to be scaled to thicknesses as low as 10 nm while retaining their ferroelectric properties; a feat that has been difficult to accomplish with conventional perovskite-based ferroelectrics using CMOS-compatible processes. However, reducing the thickness limit of HfO2-based ferroelectric thin films below the sub-5-nm thickness regime while preserving their ferroelectric property remains a formidable challenge. This is because both the structural factors of HfO2, including polymorphism and orientation, and the electrical factors of HfO2-based devices, such as the depolarization field, are known to be highly dependent on the HfO2 thickness. Accordingly, when the thickness of HfO2 drops below 5 nm, these factors will become even more crucial. In this regard, the size effect of HfO2-based ferroelectric thin films is thoroughly discussed in the present review. The impact of thickness on the ferroelectric property of HfO2-based thin films and the electrical performance of HfO2-based ferroelectric semiconductor devices, such as ferroelectric random access memory, ferroelectric field-effect-transistor, and ferroelectric tunnel junction, is extensively discussed from the perspective of fundamental theory and experimental results. Finally, recent developments and reports on achieving ferroelectric HfO2 at sub-5 nm thickness regime and their applications are discussed.

A Comprehensive Categorization of Micro/Nanomechanical Resonators and Their Practical Applications from an Engineering Perspective: A Review

“…A large surface‐to‐volume ratio results in an increase in surface energy, which obviously affects on the nanomechanical motion of nanoresonators, and consequently their resonant frequencies. [ 108–112 ]…”

Self‐Assembled Lanthanum Oxide Nanoflakes by Electrodeposition Technique for Resistive Switching Memory and Artificial Synaptic Devices

“…In recent years, various research groups are using electrochemical deposition techniques for the fabrication of different RS devices. [ 27–29 ] In recent times, many studies have been reported on electrochemically synthesized ZnO, [ 30 ] TiO 2 , [ 31,32 ] Ta 2 O 5 , [ 33 ] HfO 2 , [ 34 ] and Cu 2 O [ 14,35 ] for RS applications. Also, few studies are being reported on the electrodeposition of lanthanum oxide (La 2 O 3 ) for various applications.…”

Hafnia-Based Ferroelectric Memory: Device Physics Strongly Correlated with Materials Chemistry

“…For this purpose, we will present potentially achievable device performance based on the literature and the adequate theory of ferroelectrics. As we reviewed before, the defect chemistry as well as interfacial redox chemistry is necessary to fully grasp the material properties and device performances, which will be discussed rather briefly focusing on their impact on device performances. ,,− …”

“…Nonetheless, the dimensional scaling of ferroelectric thin films strongly affects their polymorphism and the resulting ferroelectricity. Furthermore, the impact of defects such as point defects such as oxygen vacancies, dead layers, and grain boundaries become strengthened with decreasing film thickness. ,,− …”

“…It should be noted that further studies to suppress the nonferroelectric phase formation and to deposit ferro- Besides polymorphism, extrinsic factors can affect various material properties and device performances. 7,34,35 Despite the importance of the effect of extrinsic factors on device physics, perspectives on the ultimately expected device performance based on the well-established physics of ferroelectric materials have yet to be comprehensively presented. In this Perspective, our purpose is to provide a perspective on ferroelectric memory devices based on the physical chemistry in (Hf,Zr)O 2 ferroelectrics.…”