A group of researchers from Tohoku University (Japan) has highlighted the potential application of sputtering to create large-area 2D van der Waals (VW) tetrachalcogenides as a new material for developing next-generation memory technology. Using this technique, they developed and identified a promising material called niobium telluride (NbTe 4 ), which has a very low melting point of approximately 447ºC (the onset temperature).
Phase change memory is a type of non-volatile memory that uses the ability of a phase change material (PCM) to go from an amorphous state, i.e., where atoms are disordered, to a crystalline state where atoms are present. closely. This change creates a reversible electrical property that can be designed to store and retrieve data.
While this field is in its infancy, phase change memory may revolutionize data storage due to its high storage density and fast read and write capabilities. Nevertheless, the complex switching technique and complicated manufacturing methods associated with these materials have presented challenges for mass production.
In recent years, van der Waals two-dimensional (2D) transition metal dichalcogenides (VTW) have emerged as a promising PCM for use in phase change memory.
Film formation by spraying
Thanks to the technique used by the researchers, sputtering is a widely used technique that involves depositing thin films of a material onto a substrate, allowing precise control over film thickness and composition. NbTe 4 films deposited from Tohoku University are initially amorphous, but can be crystallized into a 2D layered crystalline phase by annealing at temperatures above 272 °C.
Unlike conventional amorphous-crystalline PCMs, NbTe 4 exhibits a low melting point and high crystallization temperature. This unique combination provides reduced reactivation energies and improved thermal stability in the amorphous phase.
After developing NbTe 4s, the researchers evaluated their switching performance. The material showed a significant reduction in kinetic energy compared to conventional phase change memory composites. The estimated 10-year data retention temperature was found to be as high as 135°C, indicating excellent thermal stability and potential for NbTe 4 to be used in high-temperature environments such as the automotive industry. In addition, NbTe 4 demonstrated fast switching speeds of approximately 30 nanoseconds, further highlighting its potential as a next-generation phase-change memory.
