Quenching of Spin Polarization Switching in Organic Multiferroic Tunnel Junctions by Ferroelectric “Ailing-Channel” in Organic Barrier

As complementary metal-oxide-semiconductor (CMOS) scaling down to sub-10 nm node, emerging technology to reduce power consumption enforced by shortchannel effects is actively pursued. [1] At single transistor level, the most effective way is to reduce operating voltage (V DD ) and subthreshold slope (SS). [2] However, SS in metal-oxide-semiconductor fieldeffect transistors (MOSFETs) is limited to 60 mV dec −1 at room temperature due to thermionic emission of carriers in the Boltzmann tail. To this end, novel concepts are proposed to design steep-slope transistors, including tunnel FET (TFET), [3] impact ionization MOS (IMOS), [4] and nanoelectromechanical FET (NEM-FET). [5] While achieving steep slope, these new device concepts sacrifice other aspects. TFETs utilize the band-to-band tunneling current and suffer from low on-state current. The IMOS needs very large bias voltage to drive impact ionization and has stability issues. For NEM-FET, speed is limited to MHz due to the moving of heavy mass. Recently, negative capacitance (NC) effect in an FE/dielectric gate stack is proposed as a possible solution to break the 60 mV dec −1 limitation. [6][7][8][9][10][11][12] HfO 2 -based FE materials are particularly attractive because of: 1) excellent CMOS-compatibility by atomic layer deposition (ALD), [13,14] 2) scalability to ultrathin thickness, [15] 3) no sacrifice of I on , [8] and 4) potential GHz operation. [16] In the original Landau-Ginzburg-Devonshire (LGD) theory, a ferroelectric below its Curie temperature is described by a doublewell free energy landscape. The two degenerate energy minima define two stable spontaneous polarization states, which can be programmed by the application of electric field. The minima of energy states are separated by a metastable region where the second-order differential of energy versus polarization is negative, defining a region of negative capacitance. [6] It has been proposed to stabilize the metastable negative capacitance region by serially adding a dielectric (DE) with parabolic energy landscape, the so-called capacitance matching. [17,18] The Landau-Khalatnikov (L-K) model shows that such quasistatic NC can theoretically give rise to sub-60 mV dec −1 switching without hysteresis in logic devices. [19] However, so far, the experimental observation of negative capacitance still cannot be fully explained by L-K model. The negative capacitance (NC) effect in ferroelectric materials provides a possible solution to break the Boltzmann tyranny and realize steep-slope field-effect transistors (FETs) with sub-60 mV dec −1 subthreshold slope (SS). HfO 2 -based ferroelectrics (FE) have attracted great attention as dielectric candidates for NCFETs due to their excellent scalability and compatibility with complementary metal-oxide-semiconductor technology. However, understanding of the ferroelectric properties of HfO 2 -based FEs, especially at reduced thickness, is still at an early stage. The quasistatic polarization relaxation behavior of ferroelectric Hf x Zr 1−x O 2 (HZO) thin fil...

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“…When for t HZO = 4 nm, we could not obtain any PFM response. We attributed this nonswitchable behavior to interface pinning effects …”

mentioning

confidence: 98%

Thickness‐Dependent Asymmetric Potential Landscape and Polarization Relaxation in Ferroelectric Hf_xZr₁₋_xO₂ Thin Films through Interfacial Bound Charges

Zhu

Ning

et al. 2019

Adv Elect Materials

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“…This agrees with the inter-diffusion between Co and Au that has been observed in organic spin valve structures when the Co/Au layers are grown at room temperature. 33 Second, we can observe a separation of The magnetic properties of the Au(5 nm)/Co(4.6 nm)/MgO(2.9 nm)/GaN sample have been measured using a SQUID and VSM. Fig.…”

Section: Resultsmentioning

confidence: 99%

Evidence of a strong perpendicular magnetic anisotropy in Au/Co/MgO/GaN heterostructures

et al. 2019

Self Cite

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“…According to this classic electrostatic model, the tunneling current strongly depends on the electronic properties of the electrode/ferroelectric interfaces in FTJs; as a result, a higher OFF/ON resistance ratio can be achieved by choosing the electrode materials carefully [156]. Reproduced from [5,157], with permission from Springer Nature, 2016 and American Chemical Society, 2018, respectively. TMR: tunnel magnetoresistance.…”

Section: Nonvolatile Memorymentioning

confidence: 99%

“…Lopez-Encarnacion et al reported a simulation of employing PVDF as barriers in MFTJs and showed that the combination of the ferroelectric polarization orientations of the barrier and the configurations of electrodes produced multiple conductance states in the devices [171]. Recently, there have been solid-state MFTJs prepared based on PVDF or its copolymers [157,172].…”

Section: Nonvolatile Memorymentioning

confidence: 99%

Characterization and Application of PVDF and Its Copolymer Films Prepared by Spin-Coating and Langmuir–Blodgett Method

et al. 2019

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Poly(vinylidene fluoride) (PVDF) and its copolymers are key polymers, displaying properties such as flexibility and electroactive responses, including piezoelectricity, pyroelectricity, and ferroelectricity. In the past several years, they have been applied in numerous applications, such as memory, transducers, actuators, and energy harvesting and have shown thriving prospects in the ongoing research and commercialization process. The crystalline polymorphs of PVDF can present nonpolar α, ε phase and polar β, γ, and δ phases with different processing methods. The copolymers, such as poly(vinylidene fluoride-trifluoroethylene) (P(VDF-TrFE)), can crystallize directly into a phase analogous to the β phase of PVDF. Since the β phase shows the highest dipole moment among polar phases, many reproducible and efficient methods producing β-phase PVDF and its copolymer have been proposed. In this review, PVDF and its copolymer films prepared by spin-coating and Langmuir–Blodgett (LB) method are introduced, and relevant characterization techniques are highlighted. Finally, the development of memory, artificial synapses, and medical applications based on PVDF and its copolymers is elaborated.

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Quenching of Spin Polarization Switching in Organic Multiferroic Tunnel Junctions by Ferroelectric “Ailing-Channel” in Organic Barrier

Cited by 16 publications

References 44 publications

Thickness‐Dependent Asymmetric Potential Landscape and Polarization Relaxation in Ferroelectric Hf_xZr₁₋_xO₂ Thin Films through Interfacial Bound Charges

Thickness‐Dependent Asymmetric Potential Landscape and Polarization Relaxation in Ferroelectric Hf_xZr₁₋_xO₂ Thin Films through Interfacial Bound Charges

Evidence of a strong perpendicular magnetic anisotropy in Au/Co/MgO/GaN heterostructures

Characterization and Application of PVDF and Its Copolymer Films Prepared by Spin-Coating and Langmuir–Blodgett Method

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Quenching of Spin Polarization Switching in Organic Multiferroic Tunnel Junctions by Ferroelectric “Ailing-Channel” in Organic Barrier

Cited by 16 publications

References 44 publications

Thickness‐Dependent Asymmetric Potential Landscape and Polarization Relaxation in Ferroelectric HfxZr1−xO2 Thin Films through Interfacial Bound Charges

Thickness‐Dependent Asymmetric Potential Landscape and Polarization Relaxation in Ferroelectric HfxZr1−xO2 Thin Films through Interfacial Bound Charges

Evidence of a strong perpendicular magnetic anisotropy in Au/Co/MgO/GaN heterostructures

Characterization and Application of PVDF and Its Copolymer Films Prepared by Spin-Coating and Langmuir–Blodgett Method

Contact Info

Product

Resources

About

Thickness‐Dependent Asymmetric Potential Landscape and Polarization Relaxation in Ferroelectric Hf_xZr₁₋_xO₂ Thin Films through Interfacial Bound Charges

Thickness‐Dependent Asymmetric Potential Landscape and Polarization Relaxation in Ferroelectric Hf_xZr₁₋_xO₂ Thin Films through Interfacial Bound Charges