In this brief, we reported the improved break- down reliability and endurance in 10-nm Hf _0.5 Zr _0.5 O ₂ (HZO) using grain boundary interruption. By inserting an amorphous Al ₂ O ₃ layer in the middle of polycrystalline HZO, grain boundaries penetrating between the electrodes were interrupted. Compared with single-layer HZO [metal-ferroelectric-metal (MFM)] and HZO/Al ₂ O ₃ [metal-ferroelectric-insulator-metal (MFIM)], the ferroelectric/insulator/ferroelectric [metal-ferroelectric-insulator-ferroelectric-metal (MFIFM)] structure exhibited $9\times $ reduction of leakage current, 0.85-V increase of breakdown (BD) voltage ( ${T}_{\text {BD}}$ ), and 0.97-V increase of voltage for 10-year time-dependent dielectric breakdown (TDDB) lifetime. Furthermore, >10 ¹⁰ endurance was achieved in MFIFM capacitor, which has more than three orders of magnitude improvement than MFM and MFIM capacitor. This work provides an effective way to enhance the reliability of HZO-based ferroelectric devices.

In this article, mechanisms of extremely low OFF-state current and abnormal negative bias stress (NBS) are systematically investigated by the varying process that contains various gas ratios and gas flows during In–Ga–Zn–O (IGZO) sputtering, and different annealing conditions. One model is proposed to indicate the level of ultralow leakage in IGZO thin-film transistor (TFT) dominated by the trap-limited conduction (TLC) along with different internal chemical states of the film, which is highly consistent with the results acquired by X-ray photoelectron spectroscopy (XPS) data. Some special leakage behaviors of devices with low oxygen-deficient defects or with high oxygen-related states are well matched the present model. Moreover, all devices show an abnormal positive threshold voltage shift ( $\Delta {V}_{\text {TH}}$ ) under NBS, which are also discussed using the similar mechanism. Following the proposed optimization strategy based on mechanism analysis, the IGZO TFT exhibits $ > 100\times $ reduction in leakage, $0.55\times $ decrease in subthreshold (SS), and $1.24\times $ increase in mobility compared with the pristine device, achieving an ultralow leakage of <10 ⁻¹⁶ A/ $\mu \text{m}$ , promising mobility of 20.2 cm ² /V·s, and good NBS stability with $\Delta {V}_{\text {TH}} < {0.38}$ V, simultaneously. Those results provide useful guidance to design IGZO-based high-density dynamic random access memory (DRAM) with long retention time, fast access time, and excellent stability under a low thermal budget.

In this letter, sub-10-nm air channel devices were fabricated with the aid of photolithography and focused ion beam (FIB) etching. Field emission (FE) properties of the device were measured under ambient conditions. The operation mechanism was discussed by means of current-voltage (I-V) curve fitting and energy band diagram analysis. On account of the extremely shrinking of nano-gap, record-high emission currents of 355.6 μA at 1 V were realized in air with a threshold voltage as low as 0.588 V. A cycle test of 200 times was also performed to verify and analyze the stability of the device. Importantly, the temporal response performance of the device was also measured. It demonstrated a high-speed and repeatable output waveform with a rise/fall time of ~ 100 ns. This study demonstrates a practical nano-fabrication technology to fabricate sub-10-nm air channel devices with ultra-low operating voltage, which can be utilized as an electrical element in high-speed and low-power integrated circuits.

In this article, we presented a new concept of ferroelectric (FE) modulated antiferroelectric (AFE) memory with independent two-step state switching and large polarization as a promising option for multibit storage in advanced technology nodes. Based on the Landau–Ginzburg–Devonshire (LGD) theory, four nonvolatile states of AFE with the built-in field can be obtained, and the step-by-step switching among four states was successfully simulated through pulse engineering; then, stable nonvolatile 2-bit storage was experimentally demonstrated in FE/AFE/FE capacitor device, and 0.97-MV/cm bipolar built-in field introduced by FE polarization switching was extracted. The FE + AFE device showed double-peak coercive electric field ( ${E}_{c}$ ) distribution and large remanent polarization ( ${P}_{r}$ ) of $16.9 ~\mu \text{C}$ /cm ² with good process stability. Finally, benefitting from the independently step-by-step switching and large density of effective FE domain, the improved multibit storage reliability was verified by kinetic Monte Carlo (KMC) modeling compared to conventional multibit technology.