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Phase change memory (PCM) technology is a strong contender for the next‐generation memory in today's data‐centric era. In3SbTe2 (IST) phase change material is recently explored due to its good thermal stability, rapid electrical switching, and significant resistance contrast for multibit storage. However, the main concern in PCM devices is the high‐energy usage during the phase switching process. Herein, a thin oxide (HfO2) layer is inserted between the IST active layer and bottom electrode in PCM device. Such a device exhibits amorphous‐to‐crystalline phase switching (crystallization or SET operation) at a lower voltage of (2.1 ± 0.1) V and 66% reduction in energy consumption compared to the device using only IST active layer. Higher temperature of 688 K is acquired in the device with the oxide layer demonstrating that the Joule heat is effectively confined by the oxide layer assisting the crystallization process in the active layer at a less voltage. Such a device also exhibits a significant resistance contrast of ≈2 orders magnitude, allowing for stable data storage. These results reveal that the switching performance of PCM device using IST phase change material is improved by the oxide layer, which is beneficial for energy‐efficient, nonvolatile data storage applications. [ABSTRACT FROM AUTHOR]

The unique property of fast and reversible switching between SET (crystalline, highly conductive) and RESET (amorphous, highly resistive) phases of phase change materials has led to its usage in non-volatile memory applications. The quest for new phase change materials with enhanced properties is of utmost importance for developing memory devices that meet the current demand for high speed, better data retention, and multi-bit storage capabilities. We report the systematic changes occurring in the optical bandgap (E g) and structural disorder (B 1 2 ) in In3SbTe2 (IST) phase change material during the transition from amorphous to crystalline phases employing UV–Vis–NIR spectroscopy. E g in IST ranges from 0.998 (amorphous) to 0.449 eV (crystalline), revealing higher bandgap values compared to widely used Ge2Sb2Te5. An increment of 22.7% in the Tauc parameter (B 1 2 ) slope, which governs the structural disorder, is also observed during the cubic transition in IST, revealing a more ordered nature of IST in the crystalline phase. Moreover, a rise in Urbach energy (E U) from 33.4 (amorphous) to 150.2 meV (crystalline) exhibits an increase in disorder at elevated temperatures owing to film defects. These findings are supported by the change in the atomic bonding upon crystallization, which is studied using X-ray Photoelectron Spectroscopy (XPS). Our XPS findings demonstrate that the amorphous phase of IST is composed of In2Te3, InSb, and InTe species with a peak area of ∼52.97%, ∼51.26%, and ∼39.83%, respectively. XPS spectra of annealed samples reveal the phases separation of IST alloy into crystalline InSb (∼60.89%) and InTe (∼64.69%) around 300 °C and then the formation of stable cubic In3SbTe2 (∼47.54%) at 400 °C. These experimental findings of the optical properties with structural changes would help distinguish the IST from the conventional phase change materials. [ABSTRACT FROM AUTHOR]