Effects of atmosphere, metal films, temperatures and holding time on the surface topography and electrical conductivity of LiNbO3 single crystals

Lian, Jianwei; Tao, Jiajia; Chai, Xiaojie; Zhang, Yan; Jiang, Anquan

doi:10.1016/j.ceramint.2019.02.008

Cited by 12 publications

(11 citation statements)

References 46 publications

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“…For pure LaNiO 3 , approximately 16% oxygen vacancies can be produced when annealing in a H 2 /Ar reducing atmosphere . In comparison with an LNO film coated by active Zn, Al, or Mg metals at the surface, the redox process is more effective with the generation of 40–60% oxygen vacancies . Moreover, the electrical conduction along with the LNO surface increases by six orders in magnitude or more than that for an uncovered metal area .…”

Section: Introductionmentioning

confidence: 98%

“…18 Moreover, the electrical conduction along with the LNO surface increases by six orders in magnitude or more than that for an uncovered metal area. 18 The oxygen vacancies function as n-type dopants in LNO and are immobile at room temperature because the mobility of 10 −12 −10 −13 cm 2 /(V•s) is low. 19−24 In this work, we fabricated embedded electrodes using the redox treatment, which involves diffusing them thickness-wise into the LNO film during the formation of memory arrays on its surface.…”

Section: Introductionmentioning

confidence: 99%

“…In comparison with an LNO film coated by active Zn, Al, or Mg metals at the surface, the redox process is more effective with the generation of 40–60% oxygen vacancies . Moreover, the electrical conduction along with the LNO surface increases by six orders in magnitude or more than that for an uncovered metal area . The oxygen vacancies function as n-type dopants in LNO and are immobile at room temperature because the mobility of 10 –12 –10 –13 cm 2 /(V·s) is low. − …”

Section: Introductionmentioning

confidence: 99%

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In-Plane Ferroelectric Domain Wall Memory with Embedded Electrodes on LiNbO₃ Thin Films

Zheng

Zhong

et al. 2021

ACS Appl. Mater. Interfaces

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With the formation of mesa-like cells at their surfaces, LiNbO3 thin films are useful for integrating high-density domain wall memory. However, the material is too hard and inert to etch the cells with inclined side edges that help to diminish polarization retention. Moreover, etching could damage the ferroelectricity of the film. To overcome these drawbacks in forming memory cells directly, we developed a technique to deposit two gapped electrodes in the film surface, without needing to etch the film. While applying an in-plane write voltage above a coercive voltage, the domain within the gap is reversibly switched along with the creation/erasure of conducting domain walls against the peripheral unswitched domain. This technique enables “on”/“off” current read of the written information. Unfortunately, the switched domain within the gap generally has poor retention and a weak wall current arises from the presence of a strong depolarization field. To overcome this problem, we fabricated a type of embedded electrode that diffuses thickness-wise into the LiNbO3 thin film to form a parallel-plate-like structure to screen the depolarization field. The switched domains now had good retention and carry large wall currents. Alternatively, without the embedded electrodes, the switched domains within the cells can be stabilized with increasing gap distance above a critical length of 320 nm. The two methods foreshadow the possibility in the future to fabricate damage-free LiNbO3 memory cells without etching.

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Section: Introductionmentioning

confidence: 98%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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In-Plane Ferroelectric Domain Wall Memory with Embedded Electrodes on LiNbO₃ Thin Films

Zheng

Zhong

et al. 2021

ACS Appl. Mater. Interfaces

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“…After cleaning of the etching residuals, a 300 nm thick Al metal layer was deposited by magnetron sputtering (PVD-75, Kurt J. Lesker) and then was annealed at 400 °C in a reducing atmosphere. The Al metal was reacted with LNO in the sidewall areas . The reactant was dissolved in the SC-1 solution at 85 °C to increase the sidewall angles after removing Al using mixed phosphoric and nitric acids.…”

Section: Experimental Methodsmentioning

confidence: 99%

Hybrid Dry and Wet Etching of LiNbO₃ Domain-Wall Memory Devices with 90° Etching Angles and Excellent Electrical Properties

Shen,

Tan,

Wang

et al. 2023

ACS Appl. Mater. Interfaces

Self Cite

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Ferroelectric domain walls, agile nanoscale interfaces of polar order, can be selectively controlled by electric fields for their position, conformation, and function, which is ultimately the key to realizing novel low-energy memory and computing structures. LiNbO 3 single-crystal domain wall memory has the advantages of high operational speed, high integration density, and virtually unlimited endurance cycles, appearing as a good solution for the next generation of highly miniaturized low-energy memories. However, the etching process poses significant challenges in the nanofabrication and high-density integration of LiNbO 3 domain-wall memories.Here, we employed a hybrid etching technique to achieve smooth sidewalls with a 90°inclined angle, leading to a 24% reduction in the coercive field and a 2.5-fold increase in the linear domain wall current density with a retention time of more than 10 6 seconds and endurance of over 10 5 writing cycles. Combined with the results of X-ray diffraction patterns and X-ray photoelectric spectra, it is concluded that the excellent electrical performance is related to the formation of an oxygen-deficient LiNbO 3−x layer on the sidewall surface during the wet chemical etching process, which is a conductive layer that reduces the thickness of the "dead" layer between the side electrodes and the LiNbO 3 cell and rectifies the diode-like wall currents with an onset voltage reduced from 1.23 to 0.28 V. These results prove the high-density integration of ferroelectric domain-wall memories at the nanoscale and provide a new strategy applicable to the development of LiNbO 3 photonic devices.

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“…By analyzing the energy spectrogram, we can obtain the relative content of individual elements in LN samples [ 60 ] and observe their chemical state via the charge variation of different elements. [ 61,62 ] Thus, the oxidation state and concentration of Nb, O, and doped atoms in LN crystals can be quantitatively determined.…”

Section: Characterization For Phase and Chemical Statementioning

confidence: 99%

Omni‐functional crystal: Advanced methods to characterize the composition and homogeneity of lithium niobate melts and crystals

Chen

et al. 2022

Exploration

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Lithium niobate (LN) is a type of multifunctional dielectric and ferroelectric crystal that is widely used in acoustic, optical, and optoelectronic devices. The performance of pure and doped LN strongly depends on various factors, including its composition, microstructure, defects, domain, and homogeneity. The structure and composition homogeneity can affect both the chemical and physical properties of LN crystals, including their density, Curie temperature, refractive index, and piezoelectric and mechanical properties. In terms of practical demands, both the composition and microstructure characterizations these crystals must range from the nanometer scale up to the millimeter and wafer scales. Therefore, LN crystals require different characterization technologies when verifying their quality for various device applications. Optical, electrical, and acoustic technologies have been developed, including x-ray diffraction, Raman spectroscopy, electron microscopy, and interferometry. To obtain detailed structural information, advanced sub-nanometer technologies are required. For general industrial demands, fast and non-destructive technologies are preferable. This review outlines the advanced methods used to characterize both the composition and homogeneity of LN melts and crystals from the micro-to wafer scale.

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Effects of atmosphere, metal films, temperatures and holding time on the surface topography and electrical conductivity of LiNbO3 single crystals

Cited by 12 publications

References 46 publications

In-Plane Ferroelectric Domain Wall Memory with Embedded Electrodes on LiNbO₃ Thin Films

In-Plane Ferroelectric Domain Wall Memory with Embedded Electrodes on LiNbO₃ Thin Films

Hybrid Dry and Wet Etching of LiNbO₃ Domain-Wall Memory Devices with 90° Etching Angles and Excellent Electrical Properties

Omni‐functional crystal: Advanced methods to characterize the composition and homogeneity of lithium niobate melts and crystals

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Effects of atmosphere, metal films, temperatures and holding time on the surface topography and electrical conductivity of LiNbO3 single crystals

Cited by 12 publications

References 46 publications

In-Plane Ferroelectric Domain Wall Memory with Embedded Electrodes on LiNbO3 Thin Films

In-Plane Ferroelectric Domain Wall Memory with Embedded Electrodes on LiNbO3 Thin Films

Hybrid Dry and Wet Etching of LiNbO3 Domain-Wall Memory Devices with 90° Etching Angles and Excellent Electrical Properties

Omni‐functional crystal: Advanced methods to characterize the composition and homogeneity of lithium niobate melts and crystals

Contact Info

Product

Resources

About

In-Plane Ferroelectric Domain Wall Memory with Embedded Electrodes on LiNbO₃ Thin Films

In-Plane Ferroelectric Domain Wall Memory with Embedded Electrodes on LiNbO₃ Thin Films

Hybrid Dry and Wet Etching of LiNbO₃ Domain-Wall Memory Devices with 90° Etching Angles and Excellent Electrical Properties