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Relation between bandgap and resistance drift in amorphous phase change materials
Martin Rütten1,2, Matthias Kaes1, Andreas Albert1
1Institute of Physics 1A, RWTH Aachen University, Sommerfeldstrasse 14, 52074 Aachen, Germany.
Scientific Reports
|December 2, 2015
Summary
Phase change materials offer fast memory but suffer resistance drift. New research shows Ag4In3Sb67Te26 has reduced drift, paving the way for improved multilevel storage devices.
Area of Science:
- Materials Science
- Solid State Physics
- Device Engineering
Background:
- Phase change materials are key for next-generation memory, bridging storage and memory access times.
- Resistance drift in amorphous phase change materials hinders multilevel storage capabilities.
- Understanding structural relaxation is crucial for mitigating drift.
Purpose of the Study:
- To investigate the temporal evolution of optical properties in amorphous phase change materials.
- To analyze the relationship between bandgap widening, dielectric constant, and activation energy.
- To identify phase change materials with reduced resistance drift.
Main Methods:
- Temporal evolution of infrared spectra measured on amorphous thin films.
- Analysis of Ag4In3Sb67Te26, GeTe, and Ge2Sb2Te5.
- Quantitative comparison with experimental data for activation energy.
Main Results:
- Annealing causes bandgap widening and decreased optical dielectric constant (ε∞) in all studied materials.
- Temporal evolution of bandgap and activation energy can be decoupled.
- Ag4In3Sb67Te26 exhibits a smaller increase in activation energy compared to bandgap widening, indicating reduced resistance drift.
Conclusions:
- Decoupling of bandgap and activation energy evolution offers a pathway to design materials with suppressed resistance drift.
- Ag4In3Sb67Te26 presents a promising candidate for phase change memory with enhanced multilevel storage stability.
- This study provides insights for developing novel phase change materials with improved performance.
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