Flexible ferroelectric thin films fabricated by North Carolina State University researchers were used to make non-volatile memory devices that are wearable and resilient. The achievement is noted for a world first: ultra-thin oxide ferroelectric film deposition onto a flexible polymer substrate.Researchers deposited an ultra-thin oxide ferroelectric film onto a flexible polymer substrate. Source: North Carolina State University

These materials are ideal for non-volatile memory devices because of their charge-storage capability, but they are typically brittle and require high-temperature processing, which destroys most polymers. By controlling the annealing heating rate, the researchers were able to demonstrate hafnium oxide film growth on plastic substrates.

The resulting capacitor exhibited ferroelectric properties with thicknesses of 20-50 nanometers, and retained ferroelectric properties under a bending radius below 8 millimeters with bending cycle up to 1,000 times.

The ferroelectric film can be used to create stable memory storage units for use in energy-efficient electronic applications in microelectromechanical systems, sensors and other devices.

The researchers used the ferroelectric film as a gate insulator to demonstrate a low voltage nonvolatile vertical organic transistor on a plastic substrate with an extrapolated date retention time of up to 10 years.