Ferroelectric RAM (FeRAM, F-RAM, or FRAM) is a random-access memory that uses a ferroelectric layer to achieve non-volatility. It stores information through the phenomenon of polarization, in which an electric dipole, like the N-S magnetic fields inside ferroelectrics, is aligned by an external electric field.
One of the significant drawbacks of FRAM is its lower storage density. And thus, to increase its storage capacity, it is necessary to integrate as many devices as possible by reducing the chip size. In the case of ferroelectrics, the reduction in physical dimension results in the disappearance of polarization, which aids in storing information in ferroelectric materials.
This is because the arrangement of ferroelectric domains, the tiny regions where the spontaneous polarization occurs, requires, in any event, a group of thousands of atoms. In this way, current research on FRAM technology focuses on diminishing the domain size, while keeping the storage capacity.
In a new study, Professor Jun Hee Lee in the School of Energy and Chemical Engineering at UNIST has proposed a new physical phenomenon that promises a fingernail-sized memory chip’s enhanced storage capacity by 1,000 times.
Scientists noticed that by adding a drop of electrical charge to semiconductor material known as ferroelectric hafnium oxide (HfO2), it is conceivable to control four individual iotas to store 1 bit of data. This pivotal exploration has overturned the existing paradigm, which is capable of storing 1 bit of data in a group of thousands of atoms, at best. When appropriately applied, a semiconductor memory can store 500 Tbit/cm2, 1,000 times greater storage than flash memory chips that are presently accessible.
Professor Jun Hee Lee in the School of Energy and Chemical Engineering at UNIST said, “The new technology, enabling storing data in individual atoms is the highest-level storage technology that has been developed so far. As HfO2 is already compatible in Si-electronics, our discovery of independently switchable polar layers could provide opportunities to realize ultra-dense and low-cost FeRAM or FeFET for memory or logic device applications.”
“Also, the possibility of unit-cell-by-unit-cell dipolar control provides different opportunities for deterministic multilevel switching, ultimately down to the angstrom scale.”
This revolutionary discovery has been supported by Samsung Research Funding and Incubation Center of Samsung Electronics and through the Future Materials Discovery program by the Ministry of Science and ICT (MSIT), as well as the Industrial Strategic Technology Development Program by the Creative Materials Discovery program by the Ministry of Trade, Industry Energy (MOTIE).
Journal Reference:
- Hyun-Jae Lee, Minseong Lee, Kyoungjun Lee, et al., “Scale-free ferroelectricity induced by flat phonon bands in HfO2,” Science, (2020). DOI: 10.1126/science.aba0067