Publications by authors named "R I Khakimov"
Article Synopsis
- The study investigates how a bottom TiO interfacial layer affects the ferroelectric properties of TiN/HfZrO/TiN capacitors, showing that adding this layer increases the polar orthorhombic phase in the HfZrO film.
- The thickness of the TiO layer significantly influences the crystalline structure of HfZrO, leading to a stabilization of the monoclinic phase at greater TiO thicknesses.
- While the TiO layer enhances retention performance by reducing oxygen vacancies and imprint effects, there are limitations in endurance due to phase transitions in the TiO layer when the effective electric field is increased.
Article Synopsis
- HfZrO (HZO) ferroelectrics show great potential for nonvolatile memory but face reliability challenges including wake-up, fatigue, and retention loss.
- A comparison of HZO-based stacks with TiN and Ru electrodes indicates that both exhibit significant wake-up and retention losses, with Ru implementation worsening fatigue due to the generation of oxygen vacancies.
- The study reveals that reliability issues in HZO capacitors depend heavily on the electrode type, suggesting that simply replacing electrodes for improved properties may not address underlying problems.
Article Synopsis
- Resistive switching (RS) device performance is influenced by the material properties of both the insulator and the bottom electrode (BE), particularly the surface roughness of the BE, which in this case is a Ru film on a TiN layer.
- The study demonstrates that increasing the thickness of the Ru films through radical-enhanced atomic layer deposition (REALD) leads to a significant rise in surface roughness and results in changes to various RS parameters such as switching voltage and resistance states.
- A simplified model links the roughness of the Ru surface to the RS characteristics by simulating field distribution and indicating that the roughness enhances local fields, leading to specific conducting filament formation, which was confirmed using conductive atomic force microscopy.
This work demonstrates by in vacuo X-ray photoelectron spectroscopy and grazing-incidence X-ray diffraction that Ru(EtCp) and O radical-enhanced atomic layer deposition, where EtCp means the ethylcyclopentadienyl group, provides the growth of either RuO or Ru thin films depending on the deposition temperature (T), while different mechanisms are responsible for the growth of RuO and Ru. The thin films deposited at temperatures ranging from 200 to 260 °C consisted of polycrystalline rutile RuO phase revealing, according to atomic force microscopy and the four-point probe method, a low roughness (∼1.7 nm at 15 nm film thickness) and a resistivity of ≈83 µΩ cm.
View Article and Find Full Text PDFGhost imaging is a quantum optics technique that uses correlations between two beams to reconstruct an image from photons that do not interact with the object being imaged. While pairwise (second-order) correlations are usually used to create the ghost image, higher-order correlations can be utilized to improve the performance. In this Letter, we demonstrate higher-order atomic ghost imaging, using entangled ultracold metastable helium atoms from an s-wave collision halo.
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