High polarization and wake-up free ferroelectric characteristics in ultrathin Hf_0.5Zr_0.5O₂ devices by control of oxygen-deficient layer

Abstract

The formation of an interfacial layer is believed to affect the ferroelectric properties in HfO2 based 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/IrO x suggest the strong effect of IrO x in controlling bottom interfacial layer formation while W/HZO/W badly suffers from interfacial layer formation. W/HZO/IrO x devices show high remnant polarization (2P r) ∼ 53 μC cm−2, 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/IrO x devices demonstrate high 2P r and 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/IrO x devices show 2P r values 13.54, 22.4, 38.23 μC cm−2 at 4 MV cm−1 and 19.96, 30.17, 48.34 μC cm−2 at 5 MV cm−1, respectively, with demonstration of wake-up free ferroelectric characteristics.

Optimizing the Ferroelectric Properties of Hf1–xZrxO2 Films via Crystal Orientation

“…These results indicate that EPA could potentially be used to reduce the dose of the wake-up treatment in HZO; however, the effectiveness of treatment would depend largely on processing conditions. Researchers have previously created WUF-HZO by optimizing the electrode/HZO interface by selecting a different electrode material 42 or by reducing the concentration of defects within the HZO by optimizing the ALD process. 43 X-ray photoelectron spectroscopy (XPS) has revealed that achieving a wake-up free state involves altering the state of oxygen in the HZO.…”

Perspective on Ferroelectric Devices: Lessons from Interfacial Chemistry

“…Figure 7(b) and (c) show the polarization−voltage (P−V) and current density−voltage (J−V) curves of the Hf 0.5 Zr 0.5 O 2 thin film deposited on the MoO x and TiN electrodes, respectively. 71 Here, 0, 5, 10, and 15% flow rates of the oxygen gas in-flow, which affect the relative ratio of oxygen gas 72 The Hf 0.5 Zr 0.5 O 2 thin film deposited on the W or IrO 2 electrode shows a higher P r than that of the Hf 0.5 Zr 0.5 O 2 thin film on the TiN electrode. It has been suggested that W and the IrO 2 bottom electrode effectively suppress the formation of nonferroelectric ILs and/or decrease the oxygen vacancy concentration.…”

“…Figure (d) and (e) show the P – V and I – V curves of the Hf 0.5 Zr 0.5 O 2 thin film deposited on the W, Pt/W, IrO 2 , and TiN bottom electrodes, respectively, with the top electrode material being all W . The Hf 0.5 Zr 0.5 O 2 thin film deposited on the W or IrO 2 electrode shows a higher P r than that of the Hf 0.5 Zr 0.5 O 2 thin film on the TiN electrode.…”

“…Copyright 2022 American Chemical Society. Figure (d) and (e) were reprinted with permission from ref . Copyright 2021 American Chemical Society.…”

Role of the electrolyte layer in CMOS-compatible and oxide-based vertical three-terminal ECRAM

“…Various devices are utilized in VMM, from a typical transistor to novel synaptic devices. 5,6,10,[12][13][14][15][16][17][18][19] A greater number of parallel connections can improve computation performance as the dot product is conducted by the parallel connections between the processing unit (logic device) and memory. Therefore, a large number of logic and memory devices must be integrated together in parallel.…”