Ferroelectrics Based on HfO2 Film

Abstract

The discovery of ferroelectricity in HfO2 thin film, which is compatible with the CMOS process, has revived interest in ferroelectric memory devices. HfO2 has been found to exhibit high ferroelectricity at a few nanometers thickness, and studies have rapidly progressed in the past decade. Ferroelectricity can be induced in HfO2 by various deposition methods and heat treatment processes. By combining ferroelectric materials with field-effect transistors, devices that combine logic and memory functions can be implemented. Ferroelectric HfO2-based devices show high potential, but there are some challenges to overcome in endurance and characterization. In this paper, we discuss the fabrication and characteristics of ferroelectric HfO2 film and various applications, including negative capacitance (NC)), Ferroelectric random-access memory (FeRAM), Ferroelectric tunnel junction (FTJ), and Ferroelectric Field-effect Transistor (FeFET).

Domain Wall Movement in Undoped Ferroelectric HfO2: A Rayleigh Analysis

“…The transition to the Rayleigh-like region occurs at the threshold field, which is E T = 0.4 MV/cm for the measured HfO 2 layers. The definition of the Rayleigh-like region was chosen so that the coefficient of determination R 2 is greater than 0.95 for the linear fits of the three dispersion coefficients (eqs 3,4,5). This results in a field strength E PS of about 0.8 MV/cm for the transition to the partial switching region.…”

“…The scalability of hafnia-based devices and the compatibility of HfO 2 with CMOS technology, known through its use as a high-K gate dielectricum, demonstrate the great potential for HfO 2 -based ferroelectric devices as semiconductor components in diverse device types . Accordingly, research on the integration of ferroelectric HfO 2 has already been carried out on a variety of different device types, such as ferroelectric random access memory (FRAM), ferroelectric tunnel junctions (FTJs), and ferroelectric field effect transistors (FeFETs). , For the fabrication of undoped and doped ferroelectric HfO 2 layers, atomic layer deposition (ALD), sputtering, pulsed laser deposition, and chemical solution deposition can be used as deposition methods …”

“…3 Accordingly, research on the integration of ferroelectric HfO 2 has already been carried out on a variety of different device types, such as ferroelectric random access memory (FRAM), ferroelectric tunnel junctions (FTJs), and ferroelectric field effect transistors (FeFETs). 4,5 For the fabrication of undoped and doped ferroelectric HfO 2 layers, atomic layer deposition (ALD), sputtering, pulsed laser deposition, and chemical solution deposition can be used as deposition methods. 6 Even though there have been almost twice as many publications on ALD for HfO 2 production as on sputtering deposition in the past three years, 7 the sputtering process offers advantages such as more adjustable process parameters and, thus, a high degree of flexibility as well as a larger deposition rate.…”

Interplay of Precursor and Plasma for The Deposition of HfO2 via PEALD: Film Growth and Dielectric Properties

“…Most importantly the reactivity of the compounds is higher which falls in line with the feature recently reported by Gordon and our group for metalorganic complexes featuring N,N'-diisopropylformamidine ligands for the ALD growth of metal oxides at low temperatures. [50,51,56] The purity of compounds 1 and 2 as well as their structure in solution was investigated by 1 H and 13 C nuclear magnetic resonance (NMR) spectroscopy, revealing the successful formation of the desired bis-substituted products. The obtained 1 H NMR spectra are shown in Figure 1 with peaks assigned to the respective protons, while the 13 C ones are summarized in Figure S1 (Supporting Information).…”

“…[12] Recently, HfO 2 layers with a thickness of a few nanometers demonstrated the potential to be implemented in ferroelectric memory devices. [13][14][15] Moreover, due to its high refractive index ranging from 1.8 to 2.2 and low absorption, [16] hafnium oxide is widely used for optical multilayer coatings for ultraviolet (UV) and infrared (IR) applications. The hardness of HfO 2 also makes it useful for the preparation of optical and protective coatings in the production of special glass types for fiber-optic products.…”