A generalized self-consistent model for quantum tunneling current in dissimilar metal-insulator-metal junction

Abstract

We study the current density-voltage (J − V) characteristics of dissimilar metal-insulator-metal (MIM) nanoscale tunneling junctions using a self-consistent quantum model. The model includes emissions from both cathode and anode, and the effects of image charge potential, space charge and exchange correlation potential. The J − V curves span three regimes: direct tunneling, field emission, and space-charge-limited regime. Unlike similar MIM junctions, the J − V curves are polarity dependent. The forward (higher work function metal is negatively biased) and reverse (higher work function metal is positively biased) bias J − V curves and their crossover behaviors are examined in detail for various regimes, over a wide range of material properties (work function of the electrodes, electron affinity and permittivity of the insulator). It is found that the asymmetry between the current density profiles increases with the work function difference between the electrodes, insulator layer thickness and relative permittivity of the insulator. This asymmetry is profound in the field emission regime and insignificant in the direct tunneling, and space charge limited regimes.

Passive Intermodulation at Contacts of Rough Conductors

“…The current magnitude depends on the size of a contact spot and thickness of an insulating layer, which are determined by the applied pressure, local temperature and deformations of the surface asperities as illustrated by the links in Figure 1. The high-power carriers are mixed and modulated at the contact nonlinearities due to variations of the contact size, temperature and resistance [27,[38][39][40]. The thermal effects and mechanical deformations develop much slower than the oscillations of the RF carriers and the tunnelling current.…”

“…The accuracy of the Simmons model (4) of MIM junctions was recently examined for thin insulator films in [26][27][28][29]. The simulated characteristics of J(V g ) in the MIM junction are shown in Figure 3 for an insulating film with a thickness of 1 nm.…”

“…PIM phenomenology has been studied for more than 40 years but still remains a nagging problem. The basic physical mechanisms of nonlinearities and PIM generation were explored in metal contacts [22][23][24][25][26][27][28][29], printed RF transmission lines [30][31][32][33][34][35][36], cable assemblies [17,18,31,[37][38][39][40] and antennas [21,[41][42][43][44][45]. The main sources of passive nonlinearities include Metal-Insulator-Metal (MIM) junctions [22][23][24][26][27][28][29], electro-thermal processes [37,40,46,47], surface roughness [32,48,49] and contact mechanical deformations [49][50][51][52][53].…”

“…The basic physical mechanisms of nonlinearities and PIM generation were explored in metal contacts [22][23][24][25][26][27][28][29], printed RF transmission lines [30][31][32][33][34][35][36], cable assemblies [17,18,31,[37][38][39][40] and antennas [21,[41][42][43][44][45]. The main sources of passive nonlinearities include Metal-Insulator-Metal (MIM) junctions [22][23][24][26][27][28][29], electro-thermal processes [37,40,46,47], surface roughness [32,48,49] and contact mechanical deformations [49][50][51][52][53]. The advent of micro-electro-mechanical systems (MEMS) has sparked extensive investigations of the electrical contacts with rough surfaces and their RF performance.…”

Multiscale modeling and numerical analyses of the electric conductivity of CNT/polymer nanocomposites taking into account the tunneling effect

“…It should be noted that for a metal–insulator–metal junction, the J‐V curve can be divided into three regimes: direct tunneling, field emission, and space‐charge‐limited regime. Zhang et al 60,61 have indicated that Simmons' equation is only accurate in the direct tunneling regime, since the electron space charge potential and the electron exchange‐correction potential inside the thin insulator films are ignored. They have further developed a self‐consistent model taking into account the effects of both space charge and exchange‐correction potential, which provide accurate estimations of the tunneling current in other regimes.…”