Electrical Characterization of Ge₂Sb₂Te₅ Phase Change Memory Cells at Cryogenic Temperatures to Investigate the Physical Phenomena that Give Rise to Resistance Drift of the Amorphous Phase

Electrical measurements of metastable amorphous Ge₂Sb₂Te₅ in the temperature range of 300 - 675 K using a waveform tailored to melt, quench and characterize cells in a single shot [1] have resulted in characterization of temperature dependent carrier activation energies that follow a parabolic behavior with a peak value of ∼377 meV at ∼465 K [2]. Measurements of cells amorphized at cryogenic temperatures give insights about the physical phenomena that give rise to resistance drift of the amorphous phase as well as the activation energy in a broader temperature range. We have performed electrical measurements in 85 – 300 K temperature range and observed resistance drift over time. As the viscosity of the material is expected to be extremely high at 85 K, we expect charge trapping to be the dominant factor for drift in amorphous Ge₂Sb₂Te₅.

References:
[1] F. Dirisaglik et al., Nanoscale 7, 16625 (2015).
[2] Sadid Muneer et al., AIP Advances 8, 065314 (2018).