Phase Change Memory Cell With Reconfigured Electrode for Lower RESET Voltage

Zhou, Shaolin; Li, Kezhou; Chen, Yihan; Liao, Shaowei; Zhang, Hong-Lin; Chan, Mansun

doi:10.1109/jeds.2019.2948254

Cited by 4 publications

(6 citation statements)

References 17 publications

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“…In recent decades, early GSTs with slow speed of crystallization to match the speed of CD writer have been dominantly used for optical disk/storage [ 87 , 88 ]. Subsequently, an increased speed of crystallization makes the GST alloy a good candidate for the next generation of non-volatile electronic memories, i.e., phase change random access memory (PCRAM) [ 85 , 86 ], which rival the mainstream flash and dynamic random-access memory (DRAM). In principle, the amorphous-to-crystalline transition is triggered by a long (electrical or laser) pulse with lower amplitude to heat GST above its crystallization temperature T crys (or glass temperature T g elsewhere), termed as “SET” for a low-resistance state in PCRAM, as shown in Figure 1 a.…”

Section: Origin Of Pcm For Active Photonicsmentioning

confidence: 99%

“…Other prevailing performances in chalcogenide PCMs include long-term stability in both amorphous and crystalline states, ultrafast phase transition at the nanosecond level, a large number of phase changes in millions of repeatable cycles, and CMOS compatibility [ 85 ]. In the early days, chalcogenide PCMs have been pursued for applications in electronic storage and optical memory, such as the phase change memory [ 85 , 86 ] and the optical compact disks (CD) and digital versatile disks (DVD) [ 87 ]. Upon a phase transition of chalcogenide PCMs, the germanium antimony telluride (GST) alloy with varied ratios of compositions [ 88 ] typically assumes large contrasts in both optical and electrical properties (i.e., refractive index, permittivity, conductivity etc.…”

Section: Introductionmentioning

confidence: 99%

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Phase Change Metasurfaces by Continuous or Quasi-Continuous Atoms for Active Optoelectronic Integration

Fan

Deng

et al. 2021

Materials

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In recent decades, metasurfaces have emerged as an exotic and appealing group of nanophotonic devices for versatile wave regulation with deep subwavelength thickness facilitating compact integration. However, the ability to dynamically control the wave–matter interaction with external stimulus is highly desirable especially in such scenarios as integrated photonics and optoelectronics, since their performance in amplitude and phase control settle down once manufactured. Currently, available routes to construct active photonic devices include micro-electromechanical system (MEMS), semiconductors, liquid crystal, and phase change materials (PCMs)-integrated hybrid devices, etc. For the sake of compact integration and good compatibility with the mainstream complementary metal oxide semiconductor (CMOS) process for nanofabrication and device integration, the PCMs-based scheme stands out as a viable and promising candidate. Therefore, this review focuses on recent progresses on phase change metasurfaces with dynamic wave control (amplitude and phase or wavefront), and especially outlines those with continuous or quasi-continuous atoms in favor of optoelectronic integration.

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Section: Origin Of Pcm For Active Photonicsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Phase Change Metasurfaces by Continuous or Quasi-Continuous Atoms for Active Optoelectronic Integration

Fan

Deng

et al. 2021

Materials

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“…In addition, the nanopatterning of such chalcogenide PCMs with similar dimensions has been intensively demonstrated particularly for electronic phase change random-access memory (PCRAM) [47,48]. More importantly, reversible phase transitions between amorphous and crystalline states have proven to be feasible when triggered by thermal, electrical or laser heating [6,45,49], which essentially enables nonvolatile active control of photonic devices with multifunctionality. Therefore, we focus on functional integration of the chalcogenide PCMs into metasurface architecture to achieve the polarization-dependent and erasable holograms.…”

Section: Introductionmentioning

confidence: 99%

Polarization-multiplexed metaholograms with erasable functionality

Zhou

Liu

Chen

et al. 2023

J. Phys. D: Appl. Phys.

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The unprecedented capability of metasurface in pixel-wise-level accurate light manipulation has enabled the realization of polarization-multiplexed metasurface holograms in a single or multiple channel. However, most metasurfaces are static and unable to realize active or tunable wave control in many scenarios. We introduce erasable functionality to the multi-channel metasurface holograms based on the active phase tuning, which is realized using the nonvolatile chalcogenide phase change alloy of GeSbSeTe (GSST). Upon the incidence of linearly or circularly polarized waves, the polarization-dependent holograms constructed by amorphous GSST elliptical pillars are achieved due to the complete phase control. The a-GSST holograms feature a subwavelength spatial resolution and an estimated efficiency ranging from 66% to 90%. Benefiting from the amorphous-to-crystalline phase transition of GSST, the hologram functionality can be totally erased since the crystallized pillars cannot provide effective propagation modes required by the anisotropic phase modulations in the operating wavelength range. The unique property of the proposed polarization-multiplexed holograms with erasable functionality offers more degrees of freedom and has potential applications in many fields such as anti-counterfeiting, encryption, and holographic sources..

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“…In writing and erasing operations, self-heating and thermoelectric effects occurring in the phase change structure work as heating sources to motivate the temperature increase, i.e., the switching process [7,8]; that is, the PCM performances are intimately linked to the microscopic properties of the phase change materials, and a fully coupled electrothermal mathematical model should be utilized to evaluate the phase transition process [9]. In [10][11][12][13], models based on a current continuity equation and thermal conduction equation were developed and validated by comparing the simulated results with measured ones.…”

Section: Introductionmentioning

confidence: 99%

Design for Ultrahigh-Density Vertical Phase Change Memory: Proposal and Numerical Investigation

et al. 2022

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The integration level is a significant index that can be used to characterize the performance of non-volatile memory devices. This paper proposes innovative design schemes for high-density integrated phase change memory (PCM). In these schemes, diploid and four-fold memory units, which are composed of nano-strip film GST-based memory cells, are employed to replace the memory unit of a conventional vertical PCM array. As the phase transformation process of the phase change material involves the coupling of electrical and thermal processes, an in-house electrothermal coupling simulator is developed to analyze the performance of the proposed memory cells and arrays. In the simulator, a proven mathematical model is used to describe the phase change mechanism, with a finite element approach implemented for numerical calculations. The characteristics of the GST-strip-based memory cell are simulated first and compared with a conventional vertical cell, with a decrease of 32% in the reset current amplitude achieved. Next, the influences of geometric parameters on the characteristics of memory cell are investigated systematically. After this, the electrothermal characteristics of the proposed vertical PCM arrays are simulated and the results indicate that they possess both excellent performance and scalability. At last, the integration densities of the proposed design schemes are compared with the reference array, with a maximum time of 5.94 achieved.

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Phase Change Memory Cell With Reconfigured Electrode for Lower RESET Voltage

Cited by 4 publications

References 17 publications

Phase Change Metasurfaces by Continuous or Quasi-Continuous Atoms for Active Optoelectronic Integration

Phase Change Metasurfaces by Continuous or Quasi-Continuous Atoms for Active Optoelectronic Integration

Polarization-multiplexed metaholograms with erasable functionality

Design for Ultrahigh-Density Vertical Phase Change Memory: Proposal and Numerical Investigation

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