Dielectric breakdown decisively determines the reliability of nano- to centimeter sized electronic devices and components. Nevertheless, a systematic investigation of this phenomenon over the ...relevant lengths scales and materials classes is still missing. Here, the thickness and permittivity-dependence of the dielectric breakdown strength of insulating crystalline and polymer materials from the millimeter down to the nanometer scale is investigated. While the dependence of breakdown strength on permittivity was found to be thickness-independent for materials in the nm–mm range, the magnitude of the breakdown strength was found to change from a thickness-independent, intrinsic regime, to a thickness-dependent, extrinsic regime. The transition-thickness is interpreted as the characteristic length of a breakdown-initiating conducting filament. The results are in agreement with a model, where the dielectric breakdown strength is defined in terms of breakdown toughness and length of a conducting filament.
Breakdown waveforms, including breakdown electric field or breakdown voltage and breakdown time, are the most direct and important parameters in the conditioning, which could help to reflect the ...conditioning process. This article studies the breakdown time characteristics of conditioning with impulse voltage under a uniform electric field in vacuum. The results show that breakdown time moves from the decreasing curve to the rising curve of the impulse voltage waveform in the conditioning process. When conditioning saturation is reached, breakdown time varies in a certain range in the rising curve of the impulse voltage waveform. The breakdown electric field increases during the conditioning and fluctuates in a certain range when conditioning saturation is reached. Breakdown time and breakdown electric field characteristics are explained by breakdown mechanism. Furthermore, a method combining breakdown time and breakdown electric field for conditioning saturation judgment is proposed.
This paper is aimed at the variation of AC and lightning impulse (LI) breakdown voltages of samples enriched with fullerene (C 60 ) nanoparticles (NPs) of natural ester, which stand out as an ...alternative to mineral oils. C 60 nanofluids with long-term stability and good dielectric properties are examined in this study on five samples for concentrations of NPs ranging 0.05 to 0.4 g/L concentrations. The AC and LI breakdown voltage measurements of each sample are repeated thirty times and the conformity of these measurements of the normal distribution is tested with the Shapiro-Wilk test. Conformity of all samples to normal distribution is accepted by this test and withstand voltages are calculated at 1%, 10% and 50% breakdown probabilities. The AC breakdown voltage performances of 0.3 and 0.4 g/L C 60 nanofluids are increased compared to natural ester. This increase rate is 5.1% and 7.8%, respectively. The withstand voltages at 1% and 10% breakdown probabilities increase by 20.2% and 13.2% compared to natural ester at 0.4 g/L C 60 nanofluid. 0.1 g/L C 60 nanofluid has 8.2% better performance than natural ester at LI breakdown voltages. Withstand voltages of 1% and 10% probability of this nanofluid are 6.5% and 7.7% higher than natural ester, respectively. These measurement results show that C 60 doped nanofluids can meet performance requirements in power system equipment with high power demands.
Impulse voltage conditioning is the key to improving the insulation performance of vacuum interrupter, which is closely related to the breakdown (BD) charge. The objective of this article is to ...propose a method for adjusting the optimum BD charge during the impulse voltage conditioning process for vacuum interrupter, based on the experimental study on the conditioning characteristics of vacuum gaps under different BD charges. In experiments, a pair of copper sphere-plane electrodes in a commercial vacuum interrupter was selected. A standard lightning impulse voltage (LIV) was applied. The limiting resistance <inline-formula> <tex-math notation="LaTeX">{R}_{\text {L}} </tex-math></inline-formula> ranged from 0 to 10 <inline-formula> <tex-math notation="LaTeX">\text{k}\Omega </tex-math></inline-formula>. The experimental results reveal that the BD charge has a significant impact on the BD voltage of vacuum gaps in the conditioning process. For copper electrodes in a vacuum with a gap distance of 2.0 mm, the optimum BD charge <inline-formula> <tex-math notation="LaTeX">{Q}_{\text {BD}} </tex-math></inline-formula> in conditioning is determined to be 1.6 mQ. Under the optimum <inline-formula> <tex-math notation="LaTeX">{Q}_{\text {BD}} </tex-math></inline-formula>, the BD voltage in the saturation region reaches 135.3 kV, which is 66.4% higher than that without the adjustment of <inline-formula> <tex-math notation="LaTeX">{Q}_{\text {BD}} </tex-math></inline-formula>. Moreover, an adjustment method during the impulse voltage conditioning process is proposed, in which the optimum <inline-formula> <tex-math notation="LaTeX">{Q}_{\text {BD}} </tex-math></inline-formula> is judged by the maximum <inline-formula> <tex-math notation="LaTeX">{Q}_{\text {BD}} </tex-math></inline-formula> on the premise of a low scatter of BD voltage under the increasing <inline-formula> <tex-math notation="LaTeX">{R}_{\text {L}} </tex-math></inline-formula>.
This letter reports the polymer passivation of field plated lateral β-Ga 2 O 3 MOSFETs with significant improvement in the breakdown voltages as compared to non-passivated devices. We show consistent ...results of higher breakdown voltages in passivated devices as compared to non-passivated devices for MOSFETs with Lgd ranging from 30μm to 70μm and across two process runs. We obtain a record high breakdown voltage of 6.72 kV for a MOSFET with L gd = 40μm giving an average field strength of 1.69 MVcm -1 . The peak drain current is ~ 3 mA/mm for L g = 2μm device with a gate source separation of 3μm. The on-resistance for the device is, R on = 13 kΩ.mm, giving a power device Figure of Merit of 7.73 kWcm -2 . The R on is high due to plasma induced damage of channel and access regions. The R on and on-current density remain unchanged after passivation. The breakdown increases with L gd up to 70μm, giving a maximum breakdown voltage of 8.03 kV.
In this brief, we reported the improved break- down reliability and endurance in 10-nm Hf 0.5 Zr 0.5 O 2 (HZO) using grain boundary interruption. By inserting an amorphous Al 2 O 3 layer in the ...middle of polycrystalline HZO, grain boundaries penetrating between the electrodes were interrupted. Compared with single-layer HZO metal-ferroelectric-metal (MFM) and HZO/Al 2 O 3 metal-ferroelectric-insulator-metal (MFIM), the ferroelectric/insulator/ferroelectric metal-ferroelectric-insulator-ferroelectric-metal (MFIFM) structure exhibited <inline-formula> <tex-math notation="LaTeX">9\times </tex-math></inline-formula> reduction of leakage current, 0.85-V increase of breakdown (BD) voltage (<inline-formula> <tex-math notation="LaTeX">{T}_{\text {BD}} </tex-math></inline-formula>), and 0.97-V increase of voltage for 10-year time-dependent dielectric breakdown (TDDB) lifetime. Furthermore, >10 10 endurance was achieved in MFIFM capacitor, which has more than three orders of magnitude improvement than MFM and MFIM capacitor. This work provides an effective way to enhance the reliability of HZO-based ferroelectric devices.
In part I of this article, the current understanding and experimental observations of the so-called first breakdown (BD) phenomena are reviewed and summarized with a focus on BD statistics and ...voltage/field acceleration models because of their critical importance to reliability projection. Experimental BD data over a wide range of dielectric materials are reviewed together in a common framework. A thorough examination of various analytic BD models with key features is provided in comparison with experimental observations. In addition, we highlight advanced numerical BD models, which bring out more detailed aspects of the BD process. This state-of-the-art review can provide researchers and engineers with a coherent, global understanding to help continue their research work in this exciting field of dielectric BD.
Magnetic tunnel junctions integrated for spin-transfer torque magnetoresistive random-access memory are by far the only known solid-state memory element that can realize a combination of fast ...read/write speed and high endurance. This paper presents a comprehensive validation of high endurance of deeply scaled perpendicular magnetic tunnel junctions (pMTJs) in light of various potential spin-transfer torque magnetoresistive random-access memory (STT-MRAM) use cases. A statistical study is conducted on the time-dependent dielectric breakdown (TDDB) properties and the dependence of the p MTJ lifetime on voltage, polarity, pulsewidth, duty cycle, and temperature. The experimental results coupled with TDDB models project >10 15 write cycles. Furthermore, this work reports system-level workload characterizations to understand the practical endurance requirements for realistic memory applications.The results suggestthat the cycling endurance of STT-MRAM is "practically unlimited," which exceeds the requirements of various memory use cases, including high-performance applications such as CPU level-2 and level-3 caches.
In this letter, the endurance property of Hf 0.5 Zr 0.5 O 2 (HZO) based ferroelectric capacitor has been improved using Ru electrodes. Compared to the widely used TiN/HZO/TiN capacitor, the Ru/HZO/Ru ...capacitor shows comparable remnant polarization (~.20μC/cm 2 ), lower leakage current (5.67×10 -5 A/cm 2 ) and higher breakdown electric field (~4 MV/cm) at room temperature. The reduction of the leakage current and the enhancement of the breakdown electric field, which are ascribed to the small number of defects and vacancies in HZO thin films with Ru electrodes, prompt the endurance improvement of HZO-based capacitor from 3 × 10 10 cycles for TiN electrodes at 3 MV/cm to more than 1.2 × 10 11 cycles for Ru electrodes at 3.5 MV/cm. This work provides an effective way to reduce the leakage current and improve the endurance property of HZO-based capacitors.
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