Direct observation of phase-change volume in contact resistance change memory using N-doped Cr2Ge2Te6 phase-change material

Abstract

As we strive for faster and denser nonvolatile memory, a two-terminal phase-change random access memory device has been developed to fulfill this pressing need. This device utilizes a phase-change material (PCM) that experiences reversible resistive switching. Our study delved into the resistive switching behavior in a nitrogen-doped Cr2Ge2Te6 (NCrGT) contact resistance change memory, which employs a T-shape cell. The results of our study were highly promising: NCrGT memory cells showed a remarkable 90% reduction in Reset energy compared to the traditional PCM Ge2Sb2Te5. This notable reduction is attributed to the smaller phase-change volume of NCrGT, which was fine-tuned by the contact property. Moreover, we found that the N dopant was robustly distributed in the CrGT matrix during switching. Furthermore, we directly observed the phase-change area of the T-shape cell using transmission electron microscopy and energy-dispersive x-ray spectroscopy. After 104 of switching, our findings revealed that failure within the cells was caused by atom migration.