Publications by authors named "Roman 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.
We have developed and characterised a stable, narrow linewidth external-cavity laser (ECL) tunable over 100 nm around 1080 nm, using a single-angled-facet gain chip. We propose the ECL as a low-cost, high-performance alternative to fibre and diode lasers in this wavelength range and demonstrate its capability through the spectroscopy of metastable helium. Within the coarse tuning range, the wavelength can be continuously tuned over 30 pm (7.
View Article and Find Full Text PDFWe present an approach for numerically solving the multimode generalized nonlinear Schrödinger equation (MM-GNLSE). We propose to transform the MM-GNLSE to a system of first-order ordinary differential equations (ODEs) that can then be solved using readily available ODE solvers, thus making modeling of pulse propagation in multimode fibers easier. The solver is verified for the simplest multimode case in which only the two orthogonal polarization states in a non-birefringent microstructured optical fiber are involved.
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