Insulator (electricity)

About: Insulator (electricity) is a research topic. Over the lifetime, 15941 publications have been published within this topic receiving 108950 citations. The topic is also known as: electrical insulator.

Flashover mechanism of polluted insulation

Abstract: When a leakage current flows over the wet polluted surface of an insulator, high-resistance dry bands form. Discharges across these dry bands usually become extinguished but, exceptionally, may develop into a flashover of the insulator. The formation of dry bands and the subsequent growth of discharges on the polluted surface of a flat-strip insulator have been studied by scanning the voltage distribution along the strip at high speed. The behaviour of an arc rooted on a water surface has been investigated and the voltage gradients in the columns of arcs burning both in air and steam have been measured. Experiments show that when a water surface flashes over the arc burns in an atmosphere of steam, and that the condition for an arc to propagate over a resistive surface is that the voltage gradient on the surface exceeds that in the arc column. On this basis the flashover voltage of a water column is predictable to within 5%.

Electric-field-induced resistive switching in a family of mott insulators: Towards a new class of RRAM memories.

Abstract: The fundamental building blocks of modern silicon-based microelectronics, such as double gate transistors in non-volatile Flash memories, are based on the control of electrical resistance by electrostatic charging. Flash memories could soon reach their miniaturization limits mostly because reliably keeping enough electrons in an always smaller cell size will become increasingly difficult . The control of electrical resistance at the nanometer scale therefore requires new concepts, and the ultimate resistance-change device is believed to exploit a purely electronic phase change such as the Mott insulator to insulator transition [2]. Here we show that application of short electric pulses allows to switch back and forth between an initial high-resistance insulating state ("0" state) and a low-resistance "metallic" state ("1" state) in the whole class of Mott Insulator compounds AM4X8 (A = Ga, Ge; M= V, Nb, Ta; X = S, Se). We found that electric fields as low as 2 kV/cm induce an electronic phase change in these compounds from a Mott insulating state to a metallic-like state. Our results suggest that this transition belongs to a new class of resistive switching and might be explained by recent theoretical works predicting that an insulator to metal transition can be achieved by a simple electric field in a Mott Insulator. This new type of resistive switching has potential to build up a new class of Resistive Random Access Memory (RRAM) with fast writing/erasing times (50 ns to 10 μs) and resistance ratios ΔR/R of the order of 25% at room temperature.

Lateral AC current flow model for metal-insulator-semiconductor capacitors

Abstract: The admittance-voltage characteristic of a metal-insulator-semiconductor capacitor is explained in the depletion-inversion range for the case in which the entire surface of the semiconductor is inverted by charges in the insulator and the frequency is too high for minority carriers to follow. Lateral ac current flow into the inverted layer beyond the field plate has to be considered. The model is verified by several experiments and a simple equivalent circuit is shown to quantitatively fit the characteristics. The lateral current model is used to explain drift in the characteristics caused by ion migration along the oxide surface under dc bias. This type of ion migration is separated from true changes of charge density within the insulator.

Breakdown in silicon oxide−A review

Abstract: A review is given concerning measurement techniques and experimental results obtained on electrical breakdown in SiO2. Breakdown dependence on parameters such as time, thickness, temperature, and electrode material are covered, as well as the effect of various high‐temperature processing steps and the effect of ion implantation. The effects of sodium in causing time‐dependent breakdown are also reviewed. Special attention is given to the intrinsic breakdown mechanism in MOS capacitors where mechanisms involving impact ionization and positive charge buildup in the insulator are favored.

Ultrathin calcium fluoride insulators for two-dimensional field-effect transistors

Abstract: Two-dimensional semiconductors could be used to fabricate ultimately scaled field-effect transistors and more-than-Moore nanoelectronic devices. However, these targets cannot be reached without appropriate gate insulators that are scalable to the nanometre range. Typically used oxides such as SiO2, Al2O3 and HfO2 are, however, amorphous when scaled, and 2D hexagonal boron nitride exhibits excessive gate leakage currents. Here, we show that epitaxial calcium fluoride (CaF2), which can form a quasi van der Waals interface with 2D semiconductors, can serve as an ultrathin gate insulator for 2D devices. We fabricate scalable bilayer MoS2 field-effect transistors with a crystalline CaF2 insulator of ~2 nm thickness, which corresponds to an equivalent oxide thickness of less than 1 nm. Our devices exhibit low leakage currents and competitive device performance characteristics, including subthreshold swings down to 90 mV dec−1, on/off current ratios up to 107 and a small hysteresis. High-performance MoS2 transistors can be created using 2-nm-thick CaF2 as a gate insulator, which forms a quasi van der Waals interface with the 2D semiconductor.