Controllable Coercive Field of Ferroelectric HfO<sub>2</sub> Films via UV-Ozone Surface Modification

Zhang, Yan; Wang, Dao; Luo, Chunlai; Cheng, Jiayun; Huo, Siying; Zhang, Beijing; Tao, Ruiqiang; Chen, Deyang; Fan, Zhen; Lu, Xubing; Liu, J.-M.

doi:10.1109/ted.2022.3164856

Cited by 6 publications

(2 citation statements)

References 41 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Alternatively, the coercive field can be tuned for instance by using hybrid ferroelectric/anti-ferroelectric stacks, [42] Hf x Zr 1-x O 2 films of various compositions, [18] or an interface modification of the bottom electrode through ultraviolet-ozone irradiation. [43] Although the last mentioned approaches allow a modification of the coercive field within similar ranges, they suffer from disadvantages like for instance polarization reduction [18] and/or hysteresis loop shape distortion. [42] Figure 8 displays the endurance characteristics.…”

Section: Resultsmentioning

confidence: 99%

Ferroelectric [HfO₂/ZrO₂] Superlattices with Enhanced Polarization, Tailored Coercive Field, and Improved High Temperature Reliability

Lehninger

Prabhu

Sünbül

et al. 2023

Advanced Physics Research

View full text Add to dashboard Cite

Modern microelectronic systems and applications demand an every increasing amount of non‐volatile memories that are fast, reliable, and consume little power. Memory concepts based on ferroelectric HfO2 like the ferroelectric field effect transistor (FeFET) and the ferroelectric random access memory (FeRAM) are promising to satisfy these requirements. As a consequence, continuing high attention is given to improve the ferroelectric properties and the reliability characteristics of the ferroelectric HfO2 films –‐ for instance by using different dopant elements, dopant concentrations, and film thicknesses. Superlattices (i.e., a periodic structure of two materials stacked upon each other) are a promising alternative approach. Herein, [HfO2/ZrO2] superlattices of various sublayer thicknesses and a constant total thickness of 10 nm are embedded into metal‐ferroelectric‐metal (MFM) capacitors and then electrically as well as structurally characterized with special focus on remanent polarization, coercive field, endurance, and high temperature reliability. Compared to a 10 nm (Hf,Zr)O2 solid solution reference film, the use of superlattice stacks significantly improves the above mentioned parameters. In addition, most of these parameters depend on the sublayer thickness, which allows, for instance, tailoring the coercive field of the whole device.

show abstract

Section: Resultsmentioning

confidence: 99%

Ferroelectric [HfO₂/ZrO₂] Superlattices with Enhanced Polarization, Tailored Coercive Field, and Improved High Temperature Reliability

Lehninger

Prabhu

Sünbül

et al. 2023

Advanced Physics Research

View full text Add to dashboard Cite

show abstract

“…The XRD analysis further confirms the above electrical testing data, as shown in Figure S2. It has reported that the diffraction peak at 30.5° corresponding to the o-phase (111), and 30.8° corresponding to the t-phase (011). − Obviously, the sample with Mo electrode shows the highest o-phase ratio (88.1%), followed by the sample with W electrode (83.3%), and the sample with ITO electrode has the lowest o-phase ratio (77.8%). In addition, the 2Pr under different cycling states are also tested, as shown in Figure d.…”

Section: Resultsmentioning

confidence: 99%

Understanding the Effect of Top Electrode on Ferroelectricity in Atomic Layer Deposited Hf_0.5Zr_0.5O₂ Thin Films

Wang

Wen

et al. 2023

ACS Appl. Mater. Interfaces

View full text Add to dashboard Cite

It is commonly believed that the impact of the top electrodes on the ferroelectricity of hafnium-based thin films is due to strain engineering. However, several anomalies have occurred that put existing theories in doubt. This work carries out a detailed study of this issue using both theoretical and experimental approaches. The 10 nm Hf0.5Zr0.5O2 (HZO) films are prepared by atomic layer deposition, and three different top capping electrodes (W/MO/ITO) are deposited by physical vapor deposition. The electrical testing finds that the strain does not completely control the ferroelectricity of the devices. The results of further piezoelectric force microscopy characterization exclude the potential interference of the top capping electrodes and interface for electrical testing. In addition, through atomic force microscopy characterization and statistical analysis, a strong correlation between the grain size of the top electrode and the grain size of the HZO film has been found, suggesting that the grain size of the top electrode can induce the formation of the grain size in HZO thin films. Finally, the first-principles calculation is carried out to understand the impact of the strain and grain size on the ferroelectric properties of HZO films. The results show that the strain is the dominant factor for ferroelectricity when the grain size is large (>10 nm). However, when the grain size becomes thinner (<10 nm), the regulation effect of grain sizes increases significantly, which could bring a series of benefits for device scaling, such as device-to-device variations, film uniformity, and domain switch consistency. This work not only completes the understanding of ferroelectricity through top electrode modulation but also provides strong support for the precise regulation of ferroelectricity of nanoscale devices and ultrathin HZO ferroelectric films.

show abstract

Low Voltage High Polarization by Optimizing Scavenged WN_x Interfacial Capping Layer at the Ru/Hf_xZr_1‐xO₂ Interface and Evidence of Fatigue Mechanism

Aich,

Senapati,

Lou

et al. 2024

Adv Materials Inter

View full text Add to dashboard Cite

In this study, the double remnant polarization (2Pr) is enhanced from ≈2 to 25 µC cm−2 at a low applied voltage of ±2 V (or from 10 to 35 µC cm−2 at a voltage of ±4 V) by decreasing the WNx interfacial capping layer (ICL) thickness from 6 to 2 nm in a novel Ru/WNx ICL/Hf0.5Zr0.5O2(HZO)/TiN structure after annealing at 400 °C in a furnace. This occurs because of the higher orthorhombic (o) plus rhombohedral (r) phases (>70%), which is analyzed by geometrical phase analysis (GPA) of high‐resolution transmission electron microscope (HRTEM) images. An optimized 2 nm WNx ICL memory capacitor shows a low coercive field (Ec) of 1.27 MV cm−1 and long endurance of > 109 cycles (remaining 2Pr value of 13.5 µC cm−2) under a low field stress of ±2 MV cm−1 and 0.1 µs hold pulse width (or ≈1.67 MHz). Even this long endurance of > 109 cycles is obtained by applying a higher stress of ±2 MV cm−1, 1 MHz, or 100 kHz. Under ±3 MV cm−1 stress, the mechanism is caused by m‐phase growth from both the HZO/TiN bottom electrode (BE) and WNx ICL/HZO interfaces, which is evidenced by HRTEM images after 2 × 107 cycles for the first time.

show abstract

Controllable Coercive Field of Ferroelectric HfO₂ Films via UV-Ozone Surface Modification

Cited by 6 publications

References 41 publications

Ferroelectric [HfO₂/ZrO₂] Superlattices with Enhanced Polarization, Tailored Coercive Field, and Improved High Temperature Reliability

Ferroelectric [HfO₂/ZrO₂] Superlattices with Enhanced Polarization, Tailored Coercive Field, and Improved High Temperature Reliability

Understanding the Effect of Top Electrode on Ferroelectricity in Atomic Layer Deposited Hf_0.5Zr_0.5O₂ Thin Films

Low Voltage High Polarization by Optimizing Scavenged WN_x Interfacial Capping Layer at the Ru/Hf_xZr_1‐xO₂ Interface and Evidence of Fatigue Mechanism

Contact Info

Product

Resources

About

Controllable Coercive Field of Ferroelectric HfO2 Films via UV-Ozone Surface Modification

Cited by 6 publications

References 41 publications

Ferroelectric [HfO2/ZrO2] Superlattices with Enhanced Polarization, Tailored Coercive Field, and Improved High Temperature Reliability

Ferroelectric [HfO2/ZrO2] Superlattices with Enhanced Polarization, Tailored Coercive Field, and Improved High Temperature Reliability

Understanding the Effect of Top Electrode on Ferroelectricity in Atomic Layer Deposited Hf0.5Zr0.5O2 Thin Films

Low Voltage High Polarization by Optimizing Scavenged WNx Interfacial Capping Layer at the Ru/HfxZr1‐xO2 Interface and Evidence of Fatigue Mechanism

Contact Info

Product

Resources

About

Controllable Coercive Field of Ferroelectric HfO₂ Films via UV-Ozone Surface Modification

Ferroelectric [HfO₂/ZrO₂] Superlattices with Enhanced Polarization, Tailored Coercive Field, and Improved High Temperature Reliability

Ferroelectric [HfO₂/ZrO₂] Superlattices with Enhanced Polarization, Tailored Coercive Field, and Improved High Temperature Reliability

Understanding the Effect of Top Electrode on Ferroelectricity in Atomic Layer Deposited Hf_0.5Zr_0.5O₂ Thin Films

Low Voltage High Polarization by Optimizing Scavenged WN_x Interfacial Capping Layer at the Ru/Hf_xZr_1‐xO₂ Interface and Evidence of Fatigue Mechanism