Phase change memory is a type of non-volatile memory that uses the ability of a phase change material (PCM) to move from an amorphous state, i.e., where the atoms are not organized, into a crystalline state, ie, where the atoms are tightly packed together. This change produces a reversible electrical property that can be engineered to store and retrieve data.
While this field is still new, phase-change memory could revolutionize data storage due to its high storage density, and faster read and write capabilities. However, the complex transfer mechanism and intricate manufacturing methods associated with these materials pose challenges for mass production.
In recent years, two-dimensional (2D) Van Der Waals (vdW) transition metal di-chalcogenides have emerged as a promising PCM for use in phase change memory.
Now, a group of researchers from Tohoku University has highlighted the potential use of sputtering to create large-area 2D vdW tetra-chalcogenides. Using this technique, they created and characterized an exceptionally good material—niobium telluride (NbTe4)—which exhibits an ultra-low melting point of approximately 447 ºC (onset temperature), which distinguishes it from other TMDs. Details of the team’s discovery have been published in the journal Advanced Materials.
“Sputtering is a widely used technique that involves depositing thin films of a material onto a substrate, which enables precise control of film thickness and composition,” explained Yi Shuang, assistant professor at Tohoku University’s Advanced Institute for Materials Research and co-author of the paper . “Our deposited NbTe4 The films are initially amorphous, but can be crystallized into a 2D layered crystalline phase by annealing at temperatures above 272 ºC.”
Unlike conventional amorphous-crystalline PCMs, such as Ge2Sb2the5 (GST), NbTe4 exhibits a low melting point and high crystallization temperature. This unique combination offers reduced reset energies and improved thermal stability of the amorphous phase.
After making NbTe4, the researchers then analyzed its switching performance. It shows a significant reduction in operational energy compared to conventional phase change memory compounds.
The estimated 10-year storage temperature data was found to be as high as 135 ºC—better than 85 ºC in GST—suggesting an excellent thermal stability and the possibility of NbTe4 to be used in high temperature environments such as the automotive industry. In addition, NbTe4 showed a fast switching speed of approximately 30 nanoseconds, further highlighting its potential as a next-generation phase change memory.
“We are opening up new possibilities for the development of high-performance phase change memory,” added Shuang. “With NbTe4The low melting point, high crystallization temperature, and excellent transfer performances, it is positioned as the ideal material to meet some of the current challenges facing today’s PCMs.”
Yi Shuang et al, NbTe4 Phase-Change Material: Breaking the Phase-Change Temperature Balance in a 2d Van Der Waals Transition-Metal Binary Chalcogenide, Advanced Materials (2023). DOI: 10.1002/adma.202303646
Provided by Tohoku University
Citation: New material shows promise for next-generation memory technology (2023, July 10) retrieved 10 July 2023 from https://phys.org/news/2023-07-material-next-generation -memory-technology.html
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