Filament Growth and Resistive Switching in Hafnium Oxide Memristive Devices

Abstract

We report on the resistive switching in TiN/Ti/HfO/TiN memristive devices. A resistive switching model for the device is proposed, taking into account important experimental and theoretical findings. The proposed switching model is validated using 2D and 3D kinetic Monte Carlo simulation models. The models are consistently coupled to the electric field and different current transport mechanisms such as direct tunneling, trap-assisted tunneling, ohmic transport, and transport through a quantum point contact have been considered. We find that the numerical results are in excellent agreement with experimentally obtained data. Important device parameters, which are difficult or impossible to measure in experiments, are calculated. This includes the shape of the conductive filament, width of filament constriction, current density, and temperature distribution. To obtain insights in the operation of the device, consecutive cycles have been simulated. Furthermore, the switching kinetics for the forming and set process for different applied voltages is investigated. Finally, the influence of an annealing process on the filament growth, especially on the filament growth direction, is discussed.

Evaluation of the Sensitivity of RRAM Cells to Optical Fault Injection Attacks

“…Oxidation or reduction processes can be determined by the applied voltage polarity. Commonly the switching mechanism is described by the defects in a material, particularly the Frenkel defect [4]. This defect is a point defect in a crystal lattice when an atom leaves the lattice site and places itself in an interstitial position.…”

“…1 shows the migration of Frenkel pairs in the TiN/Ti/Al:HfO2/TiN stack. The details about the influence of the fabrication process on the CF growth direction can be found in [4]. The Ti layer acts as a scavenging layer for the oxygen atoms.…”

Electro-thermal transport in disordered nanostructures: a modeling perspective

“…First of all, most KMC models are two-dimensional, although three-dimensional implementations have been recently demonstrated. 36,37 Second of all, cubic grids have difficulty treating amorphous structures, and materials with a non-cubic lattice are only approximately represented. Lastly, the switching layer, contrary to the lament, is described as a continuum, rather than at an atomic level.…”

“…2658 | Nanoscale Adv., 2020, The dependence of the GFs and self-energies on the energy E and frequency u has been le out in the above equations and substituted by D + and G + for the scattering self-energies, to emphasize the interplay between the electron and phonon populations. Eqn (33) and (34) now depend on eqn (36) and (37) and vice versa. These two sets of equations must be solved iteratively until convergence is reached.…”

Direct Observation of Structural Deformation Immunity for Understanding Oxygen Plasma Treatment-Enhanced Resistive Switching in HfOx-Based Memristive Devices

“…The resistive switching (RS) modes in RRAM devices can either be unipolar and bipolar. During bipolar RS mode, the devices transform from high-resistance state (HRS) to low-resistance state (LRS) at one polarity (defined as SET) and regain the original resistive state at reverse polarity (defined as RESET), whereas for the unipolar RS mode a change in polarity is not required [6]. A filamentary switching mechanism has been proposed to explain the RS phenomenon by the formation/rupture of nanoscale conductive filament (CF) [7].…”