Compositionally matched nitrogen-doped Ge2Sb2Te5/Ge2Sb2Te5 superlattice-like structures for phase change random access memory

Tan, C. S.; Shi, Luping; Zhao, Rong; Guo, Qiang; Li, Yang; Yang, Yi Yan; Chong, Tow Chong; Malen, Jonathan A.; Ong, Wee‐Liat; Schlesinger, T. E.; Bain, J.A.

doi:10.1063/1.4823551

Cited by 10 publications

(6 citation statements)

References 24 publications

(31 reference statements)

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“…Regarding the SLL films synthesized at room temperature, the sublayers are usually amorphous or have poor crystallinity (Chong et al, 2006;Lu et al, 2012;Chia Tan et al, 2013). Similar situation was observed for the Sb 2 Te 3 /TiTe 2 SLL samples, as well as the pure Sb 2 Te 3 and TiTe 2 films grown on SiO 2 substrates (Supplementary Figure S1).…”

Section: Crystal Orientation and Morphologysupporting

confidence: 57%

“…Many efforts, e.g., superlattice-like (SLL) (Chong et al, 2006;Lu et al, 2012;Chia Tan et al, 2013) and superlattice (SL) (Simpson et al, 2011;Soeya et al, 2013;Takaura et al, 2014) PCM architectures, have been made to address the issue of limited endurance, attempting to tailor the 3D phase transitions into 2D fashion. However, both schemes encounter difficulties in maintaining a reliable 2D structural transformation upon repeated programming, because the RESET operations must be cautiously performed to avoid local overheating; otherwise the multilayers may melt together and then quench into a mixed amorphous phase (Simpson et al, 2011;Li et al, 2018), as the melting temperatures (T m , being ∼900-1,000 K) of the adopted PCMs in SLL or SL architectures are quite close (Chong et al, 2006;Simpson et al, 2011;Lu et al, 2012;Chia Tan et al, 2013;Soeya et al, 2013;Takaura et al, 2014). In addition, the growth condition must be tightly controlled to construct Ge(Sn)Te/Sb 2 Te 3 SLs as Ge(Sn)Te is chemically reactive and may alloy into Ge(Sn)SbTe-like compounds easily during synthesis (Li et al, 2018).…”

Section: Introductionmentioning

confidence: 99%

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Reliable 2D Phase Transitions for Low-Noise and Long-Life Memory Programming

Ding

Chen

et al. 2021

Front. Nanotechnol.

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Extending cycling endurance and suppressing programming noise of phase-change random-access memory (PCRAM) are the key challenges with respect to the development of nonvolatile working memory and high-accuracy neuromorphic computing devices. However, the large-scale atomic migration along electrical pulse direction in the unconstrained three-dimensional phase transitions of the phase-change materials (PCMs) induces big resistance fluctuations upon repeated programming and renders the classic PCRAM devices into premature failure with limited cycling endurance. Previous efforts of superlattice-like and superlattice PCM schemes cannot effectively resolve such issues. In this work, we demonstrated that, through fine-tuning the sputtering techniques, a phase-change heterostructure (PCH) of Sb2Te3/TiTe2 can be successfully constructed. In contrast to its superlattice-like counterpart with inferior crystal quality, the well-textured PCH architecture ensures the reliable (well-confined) two-dimensional phase transitions, promoting an ultralow-noise and long-life operation of the PCRAM devices. Our study thus provides a useful reference for better manufacturing the PCH architecture and further exploring the excellent device performances and other new physics.

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Section: Crystal Orientation and Morphologysupporting

confidence: 57%

Section: Introductionmentioning

confidence: 99%

Reliable 2D Phase Transitions for Low-Noise and Long-Life Memory Programming

Ding

Chen

et al. 2021

Front. Nanotechnol.

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“…Nanostructures positively impact the physical properties of PCMs with respect to the single crystal analogues. Within this framework, “superlattice-like” chalcogenides have been developed, where nano-scale GeTe and Sb 2 Te 3 units are alternatively deposited at room temperature18192021. They are shown to switch between a polycrystalline and an amorphous phase and to operate with lower power threshold and faster switching time.…”

mentioning

confidence: 99%

“…They are shown to switch between a polycrystalline and an amorphous phase and to operate with lower power threshold and faster switching time. Indeed, such stacking layout might cause a reduction of thermal transport, which enables a higher temperature raise for the same absorbed power18192021. Recently, by increasing the deposition temperature (~250 °C) and by reducing the GeTe sublayer thickness (down to 1 nm), interfacial PCMs (iPCMs) have been designed22.…”

mentioning

confidence: 99%

Revisiting the Local Structure in Ge-Sb-Te based Chalcogenide Superlattices

Casarin

Caretta

Momand

et al. 2016

Sci Rep

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The technological success of phase-change materials in the field of data storage and functional systems stems from their distinctive electronic and structural peculiarities on the nanoscale. Recently, superlattice structures have been demonstrated to dramatically improve the optical and electrical performances of these chalcogenide based phase-change materials. In this perspective, unravelling the atomistic structure that originates the improvements in switching time and switching energy is paramount in order to design nanoscale structures with even enhanced functional properties. This study reveals a high-resolution atomistic insight of the [GeTe/Sb 2 Te 3 ] interfacial structure by means of Extended X-Ray Absorption Fine Structure spectroscopy and Transmission Electron Microscopy. Based on our results we propose a consistent novel structure for this kind of chalcogenide superlattices.The need for fast and efficient management of information stimulates research on materials that can be switched on nanometer length scales and sub-nanosecond time scales. Phase-Change materials (PCMs) possess a unique property portfolio, which is ideally suited for memory device applications [1][2][3][4][5][6] . A PCM is identified by its ability of switching rapidly and reversibly between a crystalline and an amorphous state, where the amorphous state is obtained by melting the crystalline state followed by rapid quenching. These two states significantly differ in their properties, such as the optical reflectivity as well as the electrical conductivity. The phase transformation is in general triggered by thermal heating, or by either electrical and optical pulses of different time duration and amplitude. The large contrast in reflectivity between these two states lays at the base of already working PCM-based optical rewritable media devices-like DVDs or Blu-Ray Disc-where information is encoded as amorphous marks in a crystalline background. The contrast in resistivity could be exploited in the next generation of electronic solid-state memories based on PCMs, which might replace the current leading storage technologies, namely FLASH and magnetic disks. Furthermore, these materials could be employed in displays or data visualization applications by combining both their optical and electronic property modulations 7 . Hence, a lot of interest and effort is currently devoted to uncover the complex physical origin of the high contrast between the two phases [8][9][10]

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“…The design principle of SLL is to achieve good endurance, high thermal stability, and rapid crystallization speed. For example, Tan et al deposited GST and N-doped GST (N-GST) film alternately and achieved both low RESET current (37% reduction) and high endurance (∼10 8 cycles) due to compositional matching between N-GST and GST, which reduced the interfacial diffusion gradient and the phase change-induced stress . Another strategy is to combine the material with good thermal stability and the alloy with fast phase change speed.…”

Section: Phase Transition For Electronic Nanodevicesmentioning

confidence: 99%

Enabling Active Nanotechnologies by Phase Transition: From Electronics, Photonics to Thermotics

et al. 2022

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Phase transitions can occur in certain materials such as transition metal oxides (TMOs) and chalcogenides when there is a change in external conditions such as temperature and pressure. Along with phase transitions in these phase change materials (PCMs) come dramatic contrasts in various physical properties, which can be engineered to manipulate electrons, photons, polaritons, and phonons at the nanoscale, offering new opportunities for reconfigurable, active nanodevices. In this review, we particularly discuss phase-transition-enabled active nanotechnologies in nonvolatile electrical memory, tunable metamaterials, and metasurfaces for manipulation of both free-space photons and in-plane polaritons, and multifunctional emissivity control in the infrared (IR) spectrum. The fundamentals of PCMs are first introduced to explain the origins and principles of phase transitions. Thereafter, we discuss multiphysical nanodevices for electronic, photonic, and thermal management, attesting to the broad applications and exciting promises of PCMs. Emerging trends and valuable applications in all-optical neuromorphic devices, thermal data storage, and encryption are outlined in the end.

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Compositionally matched nitrogen-doped Ge2Sb2Te5/Ge2Sb2Te5 superlattice-like structures for phase change random access memory

Cited by 10 publications

References 24 publications

Reliable 2D Phase Transitions for Low-Noise and Long-Life Memory Programming

Reliable 2D Phase Transitions for Low-Noise and Long-Life Memory Programming

Revisiting the Local Structure in Ge-Sb-Te based Chalcogenide Superlattices

Enabling Active Nanotechnologies by Phase Transition: From Electronics, Photonics to Thermotics

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