Signatures of Ge2Sb2Te5 film at structural transitions

Vinod, E. M.; Naik, Ramakanta; Ganesan, R.; Sangunni, K. S.

doi:10.1016/j.jnoncrysol.2012.07.021

Cited by 22 publications

(17 citation statements)

References 24 publications

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“…Upon heating, GST films crystallize to NaCl structure and then to hexagonal structure at 150°C and 250°C respectively13. Ag doped GST show direct amorphous to NaCl transition and no indication of hexagonal phase transition in the studied temperature range (up to 300°C)9.…”

Section: Resultsmentioning

confidence: 92%

Structural transition and enhanced phase transition properties of Se doped Ge2Sb2Te5 alloys

Vinod

Ramesh

Sangunni

2015

Sci Rep

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Amorphous Ge2Sb2Te5 (GST) alloy, upon heating crystallize to a metastable NaCl structure around 150°C and then to a stable hexagonal structure at high temperatures (≥250°C). It has been generally understood that the phase change takes place between amorphous and the metastable NaCl structure and not between the amorphous and the stable hexagonal phase. In the present work, it is observed that the thermally evaporated (GST)1-xSex thin films (0 ≤ x ≤ 0.50) crystallize directly to the stable hexagonal structure for x ≥ 0.10, when annealed at temperatures ≥ 150°C. The intermediate NaCl structure has been observed only for x < 0.10. Chemically ordered network of GST is largely modified for x ≥ 0.10. Resistance, thermal stability and threshold voltage of the films are found to increase with the increase of Se. The contrast in electrical resistivity between the amorphous and crystalline phases is about 6 orders of magnitude. The increase in Se shifts the absorption edge to lower wavelength and the band gap widens from 0.63 to 1.05 eV. Higher resistance ratio, higher crystallization temperature, direct transition to the stable phase indicate that (GST)1-xSex films are better candidates for phase change memory applications.

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Section: Resultsmentioning

confidence: 92%

Structural transition and enhanced phase transition properties of Se doped Ge2Sb2Te5 alloys

Vinod

Ramesh

Sangunni

2015

Sci Rep

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“…). In general, crystallization of Ge 2 Sb 2 Te 5 thin films leads to an increase of grain size and surface roughness . The roughening process prevails in this case.…”

Section: Resultsmentioning

confidence: 97%

Isothermal crystallization of Ge₂Sb₂Te₅ amorphous thin films and estimation of information reliability of PCM cells

Kozyukhin

Vorobyov

Шерченков

et al. 2016

Physica Status Solidi (a)

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The statistical approach based on Kolmogorov's theory of metal solidification is used as the basis for a prediction of data retention time in phase change memory devices as a function of temperature of an active medium. We compared the results of theoretical simulation with the experimental results of isothermal annealing of Ge2Sb2Te5 thin films with various time and temperature regimes, and good agreement between the theoretical and experimental results was found.

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“…The bulk Te Raman spectra presents two peaks: one at 121 cm −1 which represents the A 1 mode and a second one at 140.8 cm −1 which represent E TO modes in crystalline Te-Te chain [44]. Considering that Te crystallizes at room temperature [45], a more adequate assignment of the two Raman peaks observed in our study would be based on Te segregation, which could be related as often reported to the photosensitivity of the GeTe film under laser irradiation of the Raman spectrometer when the film thickness is thinner rather than GeTe crystallization. We note, however, that parallel measurements using 785 nm excitation showed no difference in the resulting Raman spectra.…”

Section: Resultsmentioning

confidence: 99%

Ge-Sb-Te Chalcogenide Thin Films Deposited by Nanosecond, Picosecond, and Femtosecond Laser Ablation

et al. 2019

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Ge-Sb-Te thin films were obtained by ns-, ps-, and fs-pulsed laser deposition (PLD) in various experimental conditions. The thickness of the samples was influenced by the Nd-YAG laser wavelength, fluence, target-to-substrate distance, and deposition time. The topography and chemical analysis results showed that the films deposited by ns-PLD revealed droplets on the surface together with a decreased Te concentration and Sb over-stoichiometry. Thin films with improved surface roughness and chemical compositions close to nominal values were deposited by ps- and fs-PLD. The X-ray diffraction and Raman spectroscopy results showed that the samples obtained with ns pulses were partially crystallized while the lower fluences used in ps- and fs-PLD led to amorphous depositions. The optical parameters of the ns-PLD samples were correlated to their structural properties.

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Signatures of Ge2Sb2Te5 film at structural transitions

Cited by 22 publications

References 24 publications

Structural transition and enhanced phase transition properties of Se doped Ge2Sb2Te5 alloys

Structural transition and enhanced phase transition properties of Se doped Ge2Sb2Te5 alloys

Isothermal crystallization of Ge₂Sb₂Te₅ amorphous thin films and estimation of information reliability of PCM cells

Ge-Sb-Te Chalcogenide Thin Films Deposited by Nanosecond, Picosecond, and Femtosecond Laser Ablation

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Signatures of Ge2Sb2Te5 film at structural transitions

Cited by 22 publications

References 24 publications

Structural transition and enhanced phase transition properties of Se doped Ge2Sb2Te5 alloys

Structural transition and enhanced phase transition properties of Se doped Ge2Sb2Te5 alloys

Isothermal crystallization of Ge2Sb2Te5 amorphous thin films and estimation of information reliability of PCM cells

Ge-Sb-Te Chalcogenide Thin Films Deposited by Nanosecond, Picosecond, and Femtosecond Laser Ablation

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Isothermal crystallization of Ge₂Sb₂Te₅ amorphous thin films and estimation of information reliability of PCM cells