High polarization and wake-up free ferroelectric characteristics in ultrathin HfZrOdevices by control of oxygen-deficient layer.

The formation of an interfacial layer is believed to affect the ferroelectric properties in HfObased ferroelectric devices. The atomic layer deposited devices continue suffering from a poor bottom interfacial condition, since the formation of bottom interface is severely affected by atomic layer deposition and annealing process. Herein, the formation of bottom interfacial layer was controlled through deposition of different bottom electrodes (BE) in device structure W/HZO/BE. The transmission electron microscopy (TEM) and x-ray photoelectron spectroscopy analyses done on devices W/HZO/W and W/HZO/IrOsuggest the strong effect of IrOin controlling bottom interfacial layer formation while W/HZO/W badly suffers from interfacial layer formation. W/HZO/IrOdevices show high remnant polarization (2) ∼ 53C cm, wake-up free endurance cycling characteristics, low leakage current with demonstration of low annealing temperature requirement as low as 350 °C, valuable for back-end-of-line integration. Further, sub-5 nm HZO thicknesses-based W/HZO/IrOdevices demonstrate high 2and wake-up free ferroelectric characteristics, which can be promising for low power and high-density memory applications. 2.2 nm, 3 nm, and 4 nm HZO based W/HZO/IrOdevices show 2values 13.54, 22.4, 38.23C cmat 4 MV cmand 19.96, 30.17, 48.34C cmat 5 MV cm, respectively, with demonstration of wake-up free ferroelectric characteristics.