Exploring “No Man's Land”—Arrhenius Crystallization of Thin-Film Phase Change Material at 1 000 000 K s−1 via Nanocalorimetry

Jie Zhao, Jian Hui, Zichao Ye, Tianxing Lai, Mikhail Y. Efremov, Hong Wang, Leslie H. Allen

Research output: Contribution to journalArticlepeer-review


Non-volatile phase-change memory (PCM) devices are based on phase-change materials such as Ge2Sb2Te5(GST). PCM requires critically high crystallization growth velocity (CGV) for nanosecond switching speeds, which makes its material-level kinetics investigation inaccessible for most characterization methods and remains ambiguous. In this work, nanocalorimetry enters this “no-man's land” with scanning rate up to 1 000 000 K s−1 (fastest heating rate among all reported calorimetric studies on GST) and smaller sample-size (10–40 nm thick) typical of PCM devices. Viscosity of supercooled liquid GST (inferred from the crystallization kinetic) exhibits Arrhenius behavior up to 290 °C, indicating its low fragility nature and thus a fragile-to-strong crossover at ≈410 °C. Thin-film GST crystallization is found to be a single-step Arrhenius process dominated by growth of interfacial nuclei with activation energy of 2.36 ± 0.14 eV. Calculated CGV is consistent with that of actual PCM cells. This addresses a 10-year-debate originated from the unexpected non-Arrhenius kinetics measured by commercialized chip-based calorimetry, which reports CGV 103−105 higher than those measured using PCM cells. Negligible thermal lag (<1.5 K) and no delamination is observed in this work. Melting, solidification, and specific heat of GST are also measured and agree with conventional calorimetry of bulk samples.

Original languageEnglish (US)
Article number2200429
JournalAdvanced Materials Interfaces
Issue number23
StatePublished - Aug 11 2022


  • Arrhenius behavior
  • crystallization growth velocity
  • nanocalorimetry
  • phase change materials
  • viscosity

ASJC Scopus subject areas

  • Mechanics of Materials
  • Mechanical Engineering


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