First demonstration and performance improvement of ferroelectric HfO&lt;inf&gt;2&lt;/inf&gt;-based resistive switch with low operation current and intrinsic diode property

Fujii, Shosuke; Kamimuta, Yuuichi; Ino, Tsunehiro; Nakasaki, Yasushi; Takaishi, Riichiro; Saitoh, Masumi

doi:10.1109/vlsit.2016.7573413

Cited by 85 publications

(101 citation statements)

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“…In general, as P r and t F increase, TER ratio increases. However, there is a constraint; depolarizing field (E depol ) should not exceed coercive field (E c ) [12]. Otherwise FTJ does not have data retention.…”

Section: Ftj Device Designmentioning

confidence: 99%

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Ferroelectric HfO₂ Tunnel Junction Memory With High TER and Multi-Level Operation Featuring Metal Replacement Process

Kobayashi

Tagawa

et al. 2019

IEEE J. Electron Devices Soc.

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We have investigated device design of HfO 2 -based ferroelectric tunnel junction (FTJ) memory. Asymmetry of dielectric screening property in top and bottom electrodes is the key for high tunneling electroresistance (TER) ratio. Thus, metal and semiconductor electrodes are proposed. There exists a design space of ferroelectric material parameters to achieve high TER ratio under the constraint of depolarizing field. We have developed an FTJ fabrication process to realize the design. Large polarization charge and symmetric switching voltage are obtained by top metal replacement process. High TER ratio >30 and multi-level cell operation have been successfully demonstrated. Retention characteristics is promising, however, endurance characteristics should be improved for reliable operation.INDEX TERMS Ferroelectric tunnel junction (FTJ), ferroelectric HfO 2 , tunneling electroresistance.

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Section: Ftj Device Designmentioning

confidence: 99%

“…Since then, there are reports on experiments and theories for FTJ using conventional FE materials [3]- [11]. Although there are several experimental reports on FTJ with FE-HfO 2 [12]- [19], however, design guideline and process issues [13] are not fully addressed yet.…”

Section: Introductionmentioning

confidence: 99%

Ferroelectric HfO₂ Tunnel Junction Memory With High TER and Multi-Level Operation Featuring Metal Replacement Process

Kobayashi

Tagawa

et al. 2019

IEEE J. Electron Devices Soc.

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“…Developments in the fabrication of nonvolatile memories using ferroelectric HfO 2 films are therefore expected to be made in ferroelectric random access memories (FeRAMs), 24,25) ferroelectric gate-FETs (FeFETs), 24,[26][27][28][29][30] and ferroelectric tunneling junctions (FTJs). 31,32) There is a concern that the coercive field (E C ) is close to the breakdown field (E BD ) in ferroelectric HfO 2 films. 33,34) Figure 1 shows an example of the electrical properties of 10-nm-thick Hf 0.5 Zr 0.5 O 2 capacitors, the fabrication process and measurement conditions of which are described in the following section.…”

Section: Introductionmentioning

confidence: 99%

Polarization switching behavior of Hf–Zr–O ferroelectric ultrathin films studied through coercive field characteristics

Migita

Ota

Yamada

et al. 2018

Jpn. J. Appl. Phys.

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The electrical properties of ferroelectric Hf-Zr-O ultrathin films, particularly the dependences of remnant polarization, leakage current, coercive field, and breakdown field on the metal composition and film thickness, are systematically examined. Physical analyses show that the Hf-Zr-O films in this experiment consist of polycrystalline grains and contain both ferroelectric and dielectric phases. It is found that changes in metal composition and thickness strongly influence the remnant polarization and the leakage current simultaneously. In contrast, the coercive field was relatively unaffected by these parameters. This particular behavior of the coercive field suggests that the polarization switching in Hf-Zr-O films is predominantly determined by the nature of nanometer-scale ferroelectric domains dispersed in the films.

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“…Recently, a lot of research has been dedicated to ferroelectric tunnel junctions (FTJ) [1–3 ], especially after the discovery of ferroelectricity in hafnium oxide [4 ]. Compared to traditional ferroelectric perovskites, hafnium oxide and its derivatives such as Hf 1− x Zr x O 2 (HZO) offer the advantage of already established CMOS compatibility, fast switching speeds and low power consumption [5 ].…”

Section: Introductionmentioning

confidence: 99%

Built‐in bias fields for retention stabilisation in hafnia‐based ferroelectric tunnel junctions

et al. 2020

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Ferroelectric tunnel junctions have recently attracted a lot of research interest, not only for memory operation but also for e.g. neuromorphic computing. Retention characteristics of these devices are of utmost importance in many applications. The authors have recently demonstrated the feasibility of double‐layered ferroelectric tunnel junctions where the ferroelectric hafnium zirconium oxide acts as the memory layer and the dielectric aluminium oxide as the tunnelling barrier. The depolarisation field from the unscreened polarisation charges that is introduced by this structure causes serious limitations on the retention behaviour due to the unintentional back‐switching of ferroelectric domains. This leads to a diminishing memory window over time. By using a built‐in bias field from different work function metal electrodes, in this case platinum and titanium nitride with 0.85 eV difference, one can shift the polarisation hysteresis curve and counteract the electric depolarisation field. This leads to a more stable on‐current over time while only marginally increasing the off‐current degradation. Extrapolation to ten years shows a much larger memory window compared to the symmetric metal electrode structure.

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First demonstration and performance improvement of ferroelectric HfO<inf>2</inf>-based resistive switch with low operation current and intrinsic diode property

Cited by 85 publications

References 5 publications

Ferroelectric HfO₂ Tunnel Junction Memory With High TER and Multi-Level Operation Featuring Metal Replacement Process

Ferroelectric HfO₂ Tunnel Junction Memory With High TER and Multi-Level Operation Featuring Metal Replacement Process

Polarization switching behavior of Hf–Zr–O ferroelectric ultrathin films studied through coercive field characteristics

Built‐in bias fields for retention stabilisation in hafnia‐based ferroelectric tunnel junctions

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First demonstration and performance improvement of ferroelectric HfO<inf>2</inf>-based resistive switch with low operation current and intrinsic diode property

Cited by 85 publications

References 5 publications

Ferroelectric HfO2 Tunnel Junction Memory With High TER and Multi-Level Operation Featuring Metal Replacement Process

Ferroelectric HfO2 Tunnel Junction Memory With High TER and Multi-Level Operation Featuring Metal Replacement Process

Polarization switching behavior of Hf–Zr–O ferroelectric ultrathin films studied through coercive field characteristics

Built‐in bias fields for retention stabilisation in hafnia‐based ferroelectric tunnel junctions

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Ferroelectric HfO₂ Tunnel Junction Memory With High TER and Multi-Level Operation Featuring Metal Replacement Process

Ferroelectric HfO₂ Tunnel Junction Memory With High TER and Multi-Level Operation Featuring Metal Replacement Process