Polarizing and depolarizing charge injection through a thin dielectric layer in a ferroelectric-dielectric bilayer.

Charge injection from the near-by-electrode can occur during ferroelectric switching in the ferroelectric-dielectric bilayer due to the high field applied to the adjacent dielectric layers. The aim of this study is to investigate the effect of the charge injection by separating the amount of switched polarization and the injected charge density. A dynamic model of the injection-involved switching is developed and exploited to elucidate the mechanism.

A Comparative Study on the Ferroelectric Performances in Atomic Layer Deposited HfZrO Thin Films Using Tetrakis(ethylmethylamino) and Tetrakis(dimethylamino) Precursors.

The chemical, physical, and electrical properties of the atomic layer deposited HfZrO thin films using tetrakis(ethylmethylamino) (TEMA) and tetrakis(dimethylamino) (TDMA) precursors are compared. The ligand of the metal-organic precursors strongly affects the residual C concentration, grain size, and the resulting ferroelectric properties. Depositing HfZrO films with the TDMA precursors results in lower C concentration and slightly larger grain size.

Morphotropic Phase Boundary of HfZr O Thin Films for Dynamic Random Access Memories.

The utilization of the morphotropic phase boundary (MPB) between the newly found ferroelectric orthorhombic phase and the tetragonal phase in an HfO-ZrO solid solution is suggested for a high-capacitance dielectric capacitor. Being different from other high- k dielectrics, where the k value decreases with decreasing film thickness, these films (Hf/Zr ratio = 6:4, 5:5, 3:7) showed increasing k values with decreasing film thicknesses in the ∼5-20 nm range. Among them, HfZrO and HfZrO films showed 47 and 43 peak k values at 6.

Dispersion in Ferroelectric Switching Performance of Polycrystalline HfZrO Thin Films.

Interests in nanoscale integrated ferroelectric devices using doped HfO-based thin films are actively reviving in academia and industry. The main driving force for the formation of the metastable non-centrosymmetric ferroelectric phase is considered to be the interface/grain boundary energy effect of the small grains in polycrystalline configuration. These small grains, however, can invoke unfavorable material properties, such as nonuniform switching performance.

Understanding the formation of the metastable ferroelectric phase in hafnia-zirconia solid solution thin films.

HfZrO (x ∼ 0.5-0.7) has been the leading candidate of ferroelectric materials with a fluorite crystal structure showing highly promising compatibility with complementary metal oxide semiconductor devices.

Voltage Drop in a Ferroelectric Single Layer Capacitor by Retarded Domain Nucleation.

Ferroelectric (FE) capacitor is a critical electric component in microelectronic devices. Among many of its intriguing properties, the recent finding of voltage drop (V-drop) across the FE capacitor while the positive charges flow in is especially eye-catching. This finding was claimed to be direct evidence that the FE capacitor is in negative capacitance (NC) state, which must be useful for (infinitely) high capacitance and ultralow voltage operation of field-effect transistors.

Giant Negative Electrocaloric Effects of Hf Zr O Thin Films.

Hafnia (HfO )-zirconia (ZrO ) solid solution films show giant positive (ΔT = 13.4 K) and negative (ΔT = -10.8 K) electrocaloric effects that can be simply controlled by tuning the Hf/Zr ratio.

Effect of Zr Content on the Wake-Up Effect in Hf1-xZrxO2 Films.

In this study, the changes in the structural and electrical properties of ferroelectric Hf1-xZrxO2 films with various Zr contents (0.26-0.70) were systematically examined during electric field cycling, resulting in a "wake-up" effect.

Time-Dependent Negative Capacitance Effects in Al2O3/BaTiO3 Bilayers.

The negative capacitance (NC) effects in ferroelectric materials have emerged as the possible solution to low-power transistor devices and high-charge-density capacitors. Although the steep switching characteristic (subthreshold swing < sub-60 mV/dec) has been demonstrated in various devices combining the conventional transistors with ferroelectric gates, the actual applications of the NC effects are still some way off owing to the inherent hysteresis problem. This work reinterpreted the hysteretic properties of the NC effects within the time domain and demonstrated that capacitance (charge) boosting could be achieved without the hysteresis from the Al2O3/BaTiO3 bilayer capacitors through short-pulse charging.

Two-step polarization switching mediated by a nonpolar intermediate phase in Hf0.4Zr0.6O2 thin films.

The broken ferroelectric hysteresis loop achieved from a Hf0.4Zr0.6O2 film was interpreted based on the first order phase transition theory.

A study on the wake-up effect of ferroelectric Hf0.5Zr0.5O2 films by pulse-switching measurement.

The appearance of ferroelectric (FE) and anti-ferroelectric (AFE) properties in HfO2-based thin films is highly intriguing in terms of both the scientific context and practical application in various electronic and energy-related devices. Interestingly, these materials showed a "wake-up effect", which refers to the increase in remanent polarization with increasing electric field cycling number before the occurrence of the fatigue effect. In this work, the wake-up effect from Hf0.