Fast Thermal Quenching on the Ferroelectric Al:HfO2 Thin Film with Record Polarization Density and Flash Memory Application

Ku, Bon‐Cheol; Choi, Seonjun; Song, Yun-Heub; Choi, Changhwan

doi:10.1109/vlsitechnology18217.2020.9265024

Cited by 24 publications

(23 citation statements)

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“…Because the tetragonal phase in YHO8 can transform to the orthorhombic phase by an electric field, the obtained ferroelectric property is governed by the volume fraction after applying an electric field. Some studies show that fast cooling improves ferroelectricity by avoiding the formation of the monoclinic phase. , Fast cooling tends to perceive the high-temperature phase. An extremely slow cooling or long-time annealing at moderate temperature, which is probably 600–800 °C for YHO8, may degrade ferroelectricity due to the formation of the monoclinic phase.…”

Section: Results and Discussionmentioning

confidence: 99%

Comprehensive Study on the Kinetic Formation of the Orthorhombic Ferroelectric Phase in Epitaxial Y-Doped Ferroelectric HfO₂ Thin Films

Tashiro

Shiraishi

Mimura

et al. 2021

ACS Appl. Electron. Mater.

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The crystal structure and ferroelectric properties of 12- to 18 nm-thick epitaxial YO1.5-HfO2 films with 5–9% YO1.5 on (111)ITO//(111)YSZ substrates are investigated to clarify the formation mechanism of the ferroelectric phase. The ferroelectric orthorhombic phase can be obtained by transformation from the higher symmetric tetragonal phase by surmounting a relatively low energy barrier. The orthorhombic phase is obtained for 6% and 7% YO1.5-doped HfO2 films by heat treatment at 1000 °C. Although the 5% YO1.5-doped HfO2 film heat-treated at 1000 °C is in a monoclinic phase, the orthorhombic phase was increased by heat treatment at 1200 °C because the high temperature promotes the phase transition from the monoclinic phase in as-deposited films to the tetragonal phase. The 8% and 9% YO1.5-doped HfO2 films have a tetragonal structure without the transition to the orthorhombic phase. Nevertheless, the 8% YO1.5-doped HfO2 film exhibits ferroelectricity by polarization-electric field hysteresis measurement. A microarea X-ray diffraction study reveals that the electric-field-induced phase transition can take place in an 8% YO1.5-doped HfO2 film. The comprehensive study of high-temperature X-ray diffraction measurements implies that the tetragonal phase in 8% YO1.5-doped HfO2 is a supercooled state. Therefore, external stimulation, such as application of an electric field, induces the transition from the tetragonal to the orthorhombic phase. The supercooled tetragonal phase can also be reduced by a slower cooling rate. These results reveal that the formed phase in YO1.5-doped HfO2 epitaxial film is not governed by the simple difference in the formation energy; rather, the kinetics is more important for obtaining the ferroelectric orthorhombic phase.

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Section: Results and Discussionmentioning

confidence: 99%

Comprehensive Study on the Kinetic Formation of the Orthorhombic Ferroelectric Phase in Epitaxial Y-Doped Ferroelectric HfO₂ Thin Films

Tashiro

Shiraishi

Mimura

et al. 2021

ACS Appl. Electron. Mater.

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“…The depletion of the hole concentration is small enough that WL1 applied with the Vpass voltage below WL2 cannot perform self-boosting operation [11,12], but on the contrary, it can be seen that the electron concentration is about 1011 cm −3 , as shown in Figure 7d. These results can be thought of as the surrounding electrons pushed by the low voltage of WL2 being attracted to the Vpass voltage of WL1, and by these electrons, WL1 can maintain the channel voltage by self-boosting operation and prevent unintended program operation.…”

Section: Simulation Results and Discussionmentioning

confidence: 97%

“…As a result of this problem, most of the resistance-changing memories studied so far do not replace mass storage devices such as Solid-State Disks (SSD) and have limited use in specialized fields such as internal memory. Among these, in the case of ferroelectric memory recently studied using HfO 2 material [7][8][9][10][11][12], it is only necessary to replace the ONO structure used in the CTF flash with the ferroelectric material. Therefore, the NAND flash structure using the ferroelectric memory basically has an advantage that the existing NAND flash structure and operation method can be used as it is.…”

Section: Introductionmentioning

confidence: 99%

A Novel Structure and Operation Scheme of Vertical Channel NAND Flash with Ferroelectric Memory for Multi String Operations

Choi

Jeong³

et al. 2020

Electronics

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In this study, the operation method of the proposed ferroelectric memory structure as a method to overcome the limitations of the existing Charge Trap Flash (CTF) memory Vertical NAND (V-NAND) structure was presented and verified through device simulation. The proposed structure and operation method applied the BiCS (Bit Cost Scalable) structure GIDL (Gate Induce Drain Leakage) deletion method to confirm that selective program operation is possible in the ferroelectric memory V-NAND (Vertical Channel NAND) structure. In particular, we confirmed that the proposed method can easily suppress the program operation by adjusting the hole density of the channel even in the “Y-mode” operation. The channel hole density adjustment that makes this possible can be easily controlled by the voltage difference between the bit line (BL) and drain select line (DSL) contacts. The proposed structure was verified through a device simulation, and as a result of the verification, it was confirmed that the channel hole can be selectively charged in the program operation. Through this, when the cell to be programmed shows the program operation of 2.3 V, the other cells do not. It was confirmed that it could be suppressed to 0.4 V.

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“… The intensity of the tensile strain across the 50 nm thick TiN film is enhanced by increasing the hydrostatic pressure from 0 to 200 atm during the HPA process (Figure g). It is well known that a large tensile strain across ferroelectrics reduces the kinetic energy barrier upon the phase transformation from the t- to o-phases, thereby strongly encouraging the formation of the o-phase. , Because we adopted Zr-rich ferroelectrics, which favor the formation of the t-phase, the HPA system was required to create a large tensile strain to decrease the kinetic energy barrier.…”

Section: Resultsmentioning

confidence: 99%

Power-Delay Area-Efficient Processing-In-Memory Based on Nanocrystalline Hafnia Ferroelectric Field-Effect Transistors

Kim

et al. 2022

ACS Appl. Mater. Interfaces

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Ferroelectric field-effect transistors (FeFETs) have attracted enormous attention for low-power and high-density nonvolatile memory devices in processing-inmemory (PIM). However, their small memory window (MW) and limited endurance severely degrade the area efficiency and reliability of PIM devices. Herein, we overcome such challenges using key approaches covering from the material to the device and array architecture. High ferroelectricity was successfully demonstrated considering the thermodynamics and kinetics, even in a relatively thick (≥30 nm) ferroelectric material that was unexplored so far. Moreover, we employed a metal−ferroelectric−metal− insulator−semiconductor architecture that enabled desirable voltage division between the ferroelectric and the metal−oxide−semiconductor FET, leading to a large MW (∼11 V), fast operation speed (<20 ns), and high endurance (∼10 11 cycles) characteristics. Subsequently, reliable and energy-efficient multiply-and-accumulation (MAC) operations were verified using a fabricated FeFET-PIM array. Furthermore, a system-level simulation demonstrated the high energy efficiency of the FeFET-PIM array, which was attributed to charge-domain computing. Finally, the proposed signed weight MAC computation achieved high accuracy on the CIFAR-10 dataset using the VGG-8 network.

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Fast Thermal Quenching on the Ferroelectric Al:HfO2 Thin Film with Record Polarization Density and Flash Memory Application

Cited by 24 publications

References 0 publications

Comprehensive Study on the Kinetic Formation of the Orthorhombic Ferroelectric Phase in Epitaxial Y-Doped Ferroelectric HfO₂ Thin Films

Comprehensive Study on the Kinetic Formation of the Orthorhombic Ferroelectric Phase in Epitaxial Y-Doped Ferroelectric HfO₂ Thin Films

A Novel Structure and Operation Scheme of Vertical Channel NAND Flash with Ferroelectric Memory for Multi String Operations

Power-Delay Area-Efficient Processing-In-Memory Based on Nanocrystalline Hafnia Ferroelectric Field-Effect Transistors

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Fast Thermal Quenching on the Ferroelectric Al:HfO2 Thin Film with Record Polarization Density and Flash Memory Application

Cited by 24 publications

References 0 publications

Comprehensive Study on the Kinetic Formation of the Orthorhombic Ferroelectric Phase in Epitaxial Y-Doped Ferroelectric HfO2 Thin Films

Comprehensive Study on the Kinetic Formation of the Orthorhombic Ferroelectric Phase in Epitaxial Y-Doped Ferroelectric HfO2 Thin Films

A Novel Structure and Operation Scheme of Vertical Channel NAND Flash with Ferroelectric Memory for Multi String Operations

Power-Delay Area-Efficient Processing-In-Memory Based on Nanocrystalline Hafnia Ferroelectric Field-Effect Transistors

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Comprehensive Study on the Kinetic Formation of the Orthorhombic Ferroelectric Phase in Epitaxial Y-Doped Ferroelectric HfO₂ Thin Films

Comprehensive Study on the Kinetic Formation of the Orthorhombic Ferroelectric Phase in Epitaxial Y-Doped Ferroelectric HfO₂ Thin Films