Ultrafast and accurate prediction of polycrystalline hafnium oxide phase-field ferroelectric hysteresis using graph neural networks.

Polycrystalline hafnium oxide emerges as a promising material for the future of nanoelectronic devices. While phase-field modeling stands as a primary choice tool for forecasting domain structure evolution and electromechanical properties of ferroelectric materials, it suffers from a high computational cost, which impedes its applicability to real-size systems. Here, we propose a Graph Neural Network (GNN) machine-learning framework to predict the ferroelectric hysteresis of polycrystalline hafnium oxide, with the goal of significantly accelerating computations in contrast to high-fidelity phase-field methods.

Integration of epitaxial LiNbOthin films with silicon technology.

Development of bulk acoustic wave filters with ultra-wide pass bands and operating at high frequencies for 5and 6generation telecommunication applications and micro-scale actuators, energy harvesters and sensors requires lead-free piezoelectric thin films with high electromechanical coupling and compatible with Si technology. In this paper, the epitaxial growth of 36°Y-X and 30°X-Y LiNbOfilms by direct liquid injection chemical vapour deposition on Si substrates by using epitaxial SrTiOlayers, grown by molecular beam epitaxy, has been demonstrated. The stability of the interfaces and chemical interactions between SrTiO, LiNbOand Si were studied experimentally and by thermodynamical calculations.

Traceable Nanoscale Measurements of High Dielectric Constant by Scanning Microwave Microscopy.

The importance of high dielectric constant materials in the development of high frequency nano-electronic devices is undeniable. Their polarization properties are directly dependent on the value of their relative permittivity. We report here on the nanoscale metrological quantification of the dielectric constants of two high-κ materials, lead zirconate titanate (PZT) and lead magnesium niobate-lead titanate (PMN-PT), in the GHz range using scanning microwave microscopy (SMM).

A new technique based on current measurement for nanoscale ferroelectricity assessment: Nano-positive up negative down.

In this paper, we propose a new procedure which aims at measuring the polarisation switching current at the nanoscale on ferroelectric thin films with the atomic force microscope tip used as a top electrode. Our technique is an adaptation of the so-called positive up negative down method commonly operated on large electrodes. The main obstacle that must be overcome to implement such measurement is the enhancement of the signal to noise ratio, in a context where the stray capacitance of the sample/tip/lever/lever holder system generates a dielectric displacement current several orders of magnitude higher than the current to be measured.

Investigation of tip-depletion-induced fail in scanning capacitance microscopy for the determination of carrier type.

Scanning capacitance microscopy (SCM) was performed on an n-type Si multilayer structure doped by phosphorus whose concentration ranges from 2×10 to 2×10cm. Three types of tips were used, i.e.

Interpretation of multiscale characterization techniques to assess ferroelectricity: The case of GaFeO.

In this paper, we propose a thorough experimental procedure to assess the ferroelectricity of thin films, and apply this procedure to Pulsed Laser Deposition grown GaFeO thin films at the macroscale by means of Polarisation-Voltage hysteresis and at the nanoscale by Piezoresponse Force Microscopy. GaFeO is a serious candidate for the multiferroicity at room temperature, being ferrimagnetic and possibly ferroelectric. However, the non-ambiguous measurement of ferroelectric polarisation of such thin films remains a challenge.

Geometric conductive filament confinement by nanotips for resistive switching of HfO2-RRAM devices with high performance.

Filament-type HfO2-based RRAM has been considered as one of the most promising candidates for future non-volatile memories. Further improvement of the stability, particularly at the "OFF" state, of such devices is mainly hindered by resistance variation induced by the uncontrolled oxygen vacancies distribution and filament growth in HfO2 films. We report highly stable endurance of TiN/Ti/HfO2/Si-tip RRAM devices using a CMOS compatible nanotip method.