Rapid crystallization of GeTe–Bi2Te3 mixed layer

Lee, Tae-Yon; Kim, Cheolkyu; Kang, Youn-Seon; Suh, Dongseok; Kim, Kijoon H. P.; Khang, Yoonho

doi:10.1063/1.2895640

Cited by 20 publications

(19 citation statements)

References 17 publications

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“…2(a). The XRD showed the typical rock-salt structure, including the same peaks reported by Lee et al [8]. The meta-stable crystalline phase was also confirmed by TEM, as shown in Fig.…”

Section: Methodssupporting

confidence: 77%

“…Fast structural phase transition allows for the achievement of sufficient reading/writing speed for PRAM devices. [8,9] To this end, Bi-or Sn-doped GeeSbeTe system and (GeTe) n (Bi 2 Te 3 ) m pseudo-binary system (GeeBieTe system) have been suggested, and their structural information and thermo-electrical properties have been investigated [3e9]. Among them, Bi-doped GeeSbeTe and GeeBieTe systems have been preferred.…”

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Chemical states of Bi-doped GeTe (Bi: 6 at.%) thin film in structural phase transition investigated by synchrotron X-ray photoelectron spectroscopy

Jung¹,

Lee²,

Kim³

et al. 2010

Current Applied Physics

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“…2(a). The XRD showed the typical rock-salt structure, including the same peaks reported by Lee et al [8]. The meta-stable crystalline phase was also confirmed by TEM, as shown in Fig.…”

Section: Methodssupporting

confidence: 77%

Section: Introductionmentioning

confidence: 99%

Chemical states of Bi-doped GeTe (Bi: 6 at.%) thin film in structural phase transition investigated by synchrotron X-ray photoelectron spectroscopy

Jung¹,

Lee²,

Kim³

et al. 2010

Current Applied Physics

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“…The SET falling time of the GST cell was observed to be 500 ns for the fully crystalline state, whereas the GBT1 cell was fully crystallized within 3 ns. The significant improvement of the crystallization speed by CVD GBT is explained by the metallic interatomic binding induced by the unpinning of the Fermi level induced by the small amount of Bi in GBT, and the reduced sensing margin with the increased Bi concentration originates from the increased amorphous conductivity of GBT, along with the increased Bi concentration [6], [10]- [12]. Fig.…”

Section: Resultsmentioning

confidence: 95%

Scalable High-Performance Phase-Change Memory Employing CVD GeBiTe

Lee

Cho

Ahn

et al. 2011

IEEE Electron Device Lett.

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We first present chemical-vapor-deposited GeBiTe (CVD GBT) in a confined cell for high-performance phase-change random access memory (PRAM). Due to the fast crystallization of GBT, we were able to reduce the speed to less than 26 ns while maintaining endurance characteristics up to 10 9 cycles. Our results indicate that the scalable PRAM device enabling the use of PRAM in dynamic RAM and storage class memory applications can be realized using CVD GBT.

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“…[ 18 ] To examine this possibility, we produced a power-time effect (PTE) diagram ( Figure 2 f), which showed the change in refl ectance as a function of applied laser power and pulse duration. The PTE diagram was obtained for a 1-μ m-thick Bi 2 Te 3 fi lm electrodeposited on the Si substrate using a static tester with writing laser optics that had a wavelength of 650 nm, a numerical aperture of 0.6, and a focused beam size of around 1 μ m (PST-1, Nanostorage).…”

Section: Phase-change Memory In Bi 2 Te 3 Nanowiresmentioning

confidence: 99%

Phase‐Change Memory in Bi₂Te₃ Nanowires

et al. 2011

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Bismuth telluride (Bi 2 Te 3 ) and its alloys are some of the best available materials for near-room-temperature thermoelectric applications. [ 1 ] In particular, Bi 2 Te 3 nanowires have been studied extensively [3][4][5] because low-dimensional thermoelectric materials are expected to have a higher fi gure of merit due to quantum confi nement effects. [ 2 ] However, memory switching behavior has never been studied in Bi 2 Te 3 nanowires. Here, we report for the fi rst time reversible memory switching effects in Bi 2 Te 3 nanowires fabricated using anodized aluminum oxide (AAO) membranes. The fi ndings show that Bi 2 Te 3 nanowires display a reversible crystalline-amorphous phase change that is induced by a temperature, laser, or electric fi eld, similar to that reported for chalcogenide materials (Ge-Sb-Te alloys, GST). [6][7][8][9] We demonstrate that Bi 2 Te 3 nanowires show considerable promise as building blocks for phase-change random access memory (PRAM).Phase-change materials are used in nonvolatile optical memory (e.g., CDs and DVDs), and are being actively investigated as the media in universal solid-state memory devices that combine rapid read and write speeds, high storage density, and non-volatility. [ 10 ] The key feature of PRAM is the reversible phase transition of the phase-change material, caused by an electrical pulse, between the crystalline (low resistivity, SET) and amorphous (high resistivity, RESET) states.A major obstacle to achieving high-density PRAM devices is the large writing currents required to generate suffi cient thermal energy for a phase change, particularly during the crystal-to-amorphous phase transition, since a high current is required for melting. To reduce the writing currents, GST nanowires have been synthesized and were shown to satisfy many of the attributes of universal non-volatile memory devices. [ 12 , 13 ] However, GST nanowires are usually synthesized using vapor transport methods at high temperatures [11][12][13] and their large-scale assembly is not yet feasible. On the other hand, Bi 2 Te 3 nanowires exhibit memory switching characteristics that are comparable to GST nanowires [ 11 , 12 ] and they can be fabricated at room temperature using AAO membranes.Furthermore, the vertical growth of nanowires on a substrate permits a high-density assembly of Bi 2 Te 3 nanowires. Here, we describe in detail the memory switching properties of Bi 2 Te 3 nanowires.We fabricated Bi 2 Te 3 nanowires using electrodeposition within the nanopores of an AAO membrane made by anodizing Al plates. The nanowire structures were examined using X-ray diffraction (XRD) and high-resolution transmission electron microscopy (HRTEM). An XRD pattern of the as-grown nanowires ( Figure 1 a) agreed with the rhombohedral crystal structure of Bi 2 Te 3 (JCPDS No. 15-0863) reported by others. [ 3 , 4 ] The spacing between adjacent planes in the HRTEM image (Figure 1 b) was 0.202 nm, which corresponded to the (110) lattice planes of the rhombohedral Bi 2 Te 3 crystal structure. In addition, the...

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Rapid crystallization of GeTe–Bi2Te3 mixed layer

Cited by 20 publications

References 17 publications

Chemical states of Bi-doped GeTe (Bi: 6 at.%) thin film in structural phase transition investigated by synchrotron X-ray photoelectron spectroscopy

Chemical states of Bi-doped GeTe (Bi: 6 at.%) thin film in structural phase transition investigated by synchrotron X-ray photoelectron spectroscopy

Scalable High-Performance Phase-Change Memory Employing CVD GeBiTe

Phase‐Change Memory in Bi₂Te₃ Nanowires

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Rapid crystallization of GeTe–Bi2Te3 mixed layer

Cited by 20 publications

References 17 publications

Chemical states of Bi-doped GeTe (Bi: 6 at.%) thin film in structural phase transition investigated by synchrotron X-ray photoelectron spectroscopy

Chemical states of Bi-doped GeTe (Bi: 6 at.%) thin film in structural phase transition investigated by synchrotron X-ray photoelectron spectroscopy

Scalable High-Performance Phase-Change Memory Employing CVD GeBiTe

Phase‐Change Memory in Bi2Te3 Nanowires

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Product

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Phase‐Change Memory in Bi₂Te₃ Nanowires