Unified reliability modeling of Ge-rich phase change memory for embedded applications

Ciocchini, Nicola; Palumbo, E.; Borghi, Massimo; Zuliani, P.; Annunziata, R.; Ielmini, Daniele

doi:10.1109/iedm.2013.6724681

Cited by 7 publications

(11 citation statements)

References 8 publications

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“…The present work extends the results of Ref. [8] by showing new experimental data and a more detailed explanation of the set/reset instabilities model. In particular, we added the comparison between PCM device with conventional active material and Ge-rich Ge-Sb-Te (Figs.…”

Section: Introductionsupporting

confidence: 86%

“…On the other hand, ePCM should also feature data retention at high temperature, e.g., 150 • C in automotive applications, and during packaging, where the temperatures can rise above 250 • C for few minutes. To satisfy these tough reliability constraints, new chalcogenide materials with improved crystallization temperature were proposed, namely Ge-rich GeSbTe [6]- [8], C-doped GeTe [9] and SiO 2doped GeTe [10].…”

Section: Introductionmentioning

confidence: 99%

“…In this work, we address data retention in ePCM with Gerich GeSbTe, where we evidence a resistance drift and decay for both the set (poly-crystalline) and the reset (amorphous) states. These effects are modeled by structural relaxation N. Ciocchini and crystallization of amorphous chalcogenide phase, possibly residing at the grain boundaries in the set state [8]. We thus develop a unified model, capable of a physical description and accurate prediction of ePCM data retention for variable annealing conditions and programmed states.…”

Section: Introductionmentioning

confidence: 99%

“…The increase of T X at higher Ge content can be attributed to the increase of tetrahedral Ge-Ge bonds [11], which stabilize the amorphous structure with respect to crystallization. PCM devices with 90 nm mushroom-type structure were fabricated using GST, alloy A or alloy B as active material [8]. annealing [8].…”

Section: Introductionmentioning

confidence: 99%

See 3 more Smart Citations

Modeling Resistance Instabilities of Set and Reset States in Phase Change Memory With Ge-Rich GeSbTe

Ciocchini

Palumbo

Borghi

et al. 2014

IEEE Trans. Electron Devices

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To satisfy the growing market demand for embedded non-volatile memory (eNVM), alternative solutions to Flash technology are currently under investigation. Among these, phase change memory (PCM) is attracting strong interest due to the low cost of integration with the CMOS front-end and good scalability. Embedded PCM (ePCM), however, must feature high reliability during both packaging and functional stages. This work studies reliability of PCM based on Ge-rich GeSbTe, providing evidence for resistance drift and decay in both the reset and set states. Set state instability is attributed to grain-boundary relaxation and grain growth. A unified model is presented, capable of predicting the reliability of set/reset states at elevated temperature.

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Section: Introductionsupporting

confidence: 86%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

Modeling Resistance Instabilities of Set and Reset States in Phase Change Memory With Ge-Rich GeSbTe

Ciocchini

Palumbo

Borghi

et al. 2014

IEEE Trans. Electron Devices

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“…Drifting of HRS may affect correct read operations, especially for multilevel cells [35]. Incomplete set results in a similar drift of LRS [36], i.e., a first resistance increase (drift) followed by a resistance decrease. This is explained by the drift and crystallization processes occurring in the remaining amorphous regions in the material.…”

Section: ) Memory Demonstratorsmentioning

confidence: 98%

Phase-Change and Redox-Based Resistive Switching Memories

2015

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Resistive memories are a collection of physico-chemical approaches where the resistance of the device is programmed and is quite nonvolatile. This paper reviews the current understanding and the future outlook, particularly toward 3-D integration, of such phase-change and electrochemical-change-based structures.ABSTRACT | This paper addresses the two main resistive switching (RS) memory technologies: phase-change memory (PCM) and redox-based resistive random access memory (ReRAM). It will review the basic concepts, the initial promises, and current state of the art, with focus on possible scaling pathways for low-power operation and dense, true 3-D memory. Recent physical insights and new potential concepts will be discussed.

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Electrical Transport in Crystalline and Amorphous Chalcogenide

Ielmini

2017

Phase Change Memory

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Phase change memory (PCM) operation relies on a combination of electrical, thermal and structural effects at the nanoscale [1-5]. Under an externally-applied electric field, electrical current flows across the device and cause power dissipation and a consequent increase of local temperature, thus inducing crystallization or melting/amorphization, depending on temperature (hence on voltage and current). The corresponding change of the device resistance can then be sensed by application of a relatively low voltage. Electrical characteristics of the crystalline and amorphous phases thus play a fundamental role in the programming and read behavior of the PCM device. The electrical current-voltage characteristics of the PCM device, for instance, control the read current margin, the programming current, and the energy consumption during memory array operation. To design the driving circuits for generating the voltage pulses for memory program and read, or for selecting the correct select device to allow selection/unselection of memory bits within a crosspoint array, the device characteristics are an essential piece of information. The same applies to sensing circuits aimed at reading the memory state. Finally, the dependence of voltage and currents on the device geometry (e.g., thickness of the active layer, diameter of the bottom electrode) plays a leading role in determining the scaling behavior of the PCM device for various technology nodes. Optimization of PCM device should include a careful consideration of the electrical behavior, in combination to structural properties (melting and crystallization point, activation energy of crystallization, etc.) and thermal characteristics (thermal conductivity, thermal boundary resistances, etc.). This chapter summarizes the fundamental electrical properties of PCM devices in both the amorphous and crystalline states. First, the band structure of crystalline and amorphous phase change materials will be studied based on the analysis of thin films of active materials. Then, the device characteristics in a PCM device including conduction and threshold switching phenomena will be shown. Finally, the effects of non-uniform resistivity, the transient phenomena after switching, and the thermo-electric effects due to the coupling of the temperature distribution with the electrical characteristics will be illustrated.

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Unified reliability modeling of Ge-rich phase change memory for embedded applications

Cited by 7 publications

References 8 publications

Modeling Resistance Instabilities of Set and Reset States in Phase Change Memory With Ge-Rich GeSbTe

Modeling Resistance Instabilities of Set and Reset States in Phase Change Memory With Ge-Rich GeSbTe

Phase-Change and Redox-Based Resistive Switching Memories

Electrical Transport in Crystalline and Amorphous Chalcogenide

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