Measurement of Onset of Structural Relaxation in Melt-Quenched Phase Change Materials

Chalcogenide phase change materials enable non-volatile, low-latency storage-class memory. They are also being explored for new forms of computing such as neuromorphic and in-memory computing. A key challenge, however, is the temporal drift in the electrical resistance of the amorphous states that encode data. Drift, caused by the spontaneous structural relaxation of the newly recreated melt-quenched amorphous phase, has consistently been observed to have a logarithmic dependence in time. Here, it is shown that this observation is valid only in a certain observable timescale. Using threshold-switching voltage as the measured variable, based on temperature-dependent and short timescale electrical characterization, the onset of drift is experimentally measured. This additional feature of the structural relaxation dynamics serves as a new benchmark to appraise the different classical models to explain drift.

Automated summary

Chalcogenide phase change materials are utilized for non-volatile, low-latency storage-class memory and new forms of computing, but face challenges with temporal drift in electrical resistance. Research shows that the efficacy of observation is influenced by the observable timescale, and experimental measurements of drift onset can be conducted using threshold-switching voltage. This additional feature of structural relaxation dynamics serves as a new benchmark for evaluating classical models explaining drift.