2023-07-26 13:45:01
A proton-mediated method that produces multiple phase transitions in ferroelectric materials could help develop high-performance memory devices, including neuromorphic computer chips, modeled after the human brain.
This has been determined by the international team of Xin He, from the King Abdullah University of Science and Technology (KAUST) in Saudi Arabia.
Ferroelectric materials, such as indium selenide, are intrinsically polarized materials that change polarity when placed in an electric field, making them attractive for creating memory technologies. In addition to operating at low voltages, the resulting memory devices have excellent read and write reliability, as well as good speeds for both operations. However, its storage capacity is low. This is because existing methods can only activate a few ferroelectric phases.
The new method is based on the protonation of indium selenide to generate a multitude of ferroelectric phases. The researchers incorporated the ferroelectric material into a silicon-supported stacked heterostructure transistor for evaluation.
They deposited a multilayer film of indium selenide on top of the heterostructure, which comprised an insulating sheet of aluminum oxide sandwiched between a layer of platinum on the bottom and porous silica on top. While the platinum layer served as the electrode for the applied voltage, the porous silica acted as the electrolyte, supplying protons to the ferroelectric film.
The researchers gradually injected or withdrawn protons from the ferroelectric film using the strategy of changing the applied voltage. In this way, several ferroelectric phases with different degrees of protonation were reversibly produced, which is crucial to implement multilevel memory devices with considerable storage capacity.
The neuromorphic chip used by the team in various tests. (Photo: © 2023 KAUST; Fei Xue)
Higher applied positive voltages drove protonation, while negative voltages of higher amplitudes depleted protonation levels to a greater extent.
Protonation levels also varied as a function of the proximity of the film layer to the silica. They reached maximum values in the lower layer, which was in contact with the silica, and decreased until reaching minimum amounts in the upper layer.
Xin He and his colleagues discuss the details of the new system in the academic journal Science Advances, under the title “Proton-mediated reversible switching of metastable ferroelectric phases with low operation voltages.” (Source: NCYT from Amazings)
#generation #memory #devices #based #proton