Flexible Inorganic Ferroelectric Thin Films for Nonvolatile Memory Devices

Next‐generation wearable electronics call for flexible nonvolatile devices for ubiquitous data storage. Thus far, only organic ferroelectric materials have shown intrinsic flexibility and processability on plastic substrates. Here, it is shown that by controlling the heating rate, ferroelectric hafnia films can be grown on plastic substrates. The resulting highly flexible capacitor with a film thickness of 30 nm yields a remnant polarization of 10 µC cm−2. Bending tests show that the film ferroelectricity can be retained under a bending radius below 8 mm with up to 1000 bending cycles. The excellent flexibility is due to the extremely thin hafnia film thickness. Using the ferroelectric film as a gate insulator, a low voltage nonvolatile vertical organic transistor is demonstrated on a plastic substrate with an extrapolated date retention time of up to 10 years. Flexible nonvolatile memory is developed using inorganic ferroelectric thin films. By controlling the heating rate, ferroelectric hafnia films can be grown on flexible substrates. Excellent bending tolerance is observed due to the thin hafnia film thickness. Making use of the film as a gate insulator, a nonvolatile vertical field‐effect transistor is demonstrated with extrapolated data retention times to 10 years.