Simplified tunnelling current calculation for MOS structures with ultra-thin oxides for conductive atomic force microscopy investigations

Influence of dielectric layer thickness on charge injection, accumulation and transport phenomena in thin silicon oxynitride layers: a nanoscale study

“…The current versus electric field curve obtained for the 6 nm-thick SiOxNy layer was fitted using the Fowler-Nordheim Tunneling (FNT) theory. In the frame of FNT the current is given by: for SiO2 layers [26]. For comparison purposes, the Schottky barrier height (SBH) was calculated in the frame of the metal-induced gap states theory accounting for the charge transfer at the metal-dielectric contact [36,37].…”

Nanoscaled Electrical Characterization

“…Assuming this reduced area is confined to the central area of the physical contact, these results explain the sub-10 nm electrical resolution observed in C-AFM measurements. To accurately quantify the electrical contact area, we measure point contact I-V curves on a 1.5 nm-thick oxide layer, and we fit them with a Fowler Nordheim tunnel (FNT) [33] model for thin dielectrics [34]. In FNT the current through the oxide is described as field assisted tunneling through the barrier formed at the injection electrode-oxide interface and has an explicit dependence on the emission area of the electrical contact (equal to the tip electrical contact area in our configuration).…”

“…In FNT the current through the oxide is described as field assisted tunneling through the barrier formed at the injection electrode-oxide interface and has an explicit dependence on the emission area of the electrical contact (equal to the tip electrical contact area in our configuration). In view of the relation between the current and the oxide thickness, this model was originally introduced by Frammelsberger et al [34] for the oxide thickness calibration of thin oxides, whereby the Hertz contact theory was used to estimate a value for the electrical contact area within the FNT equation and the oxide thickness was calculated as a fitting variable. Depending on the coating or shape of the tip e.g.…”

“…Depending on the coating or shape of the tip e.g. Co/Cr, Pt/Ir or diamond, the values for the emission area in literature range from 10 to 500 nm 2 [34,35].…”

Local inhomogeneities resolved by scanning probe techniques and their impact on local 2DEG formation in oxide heterostructures

“…A tunneling mechanism is most likely responsible for current in these structures, as the recorded I ( V ) curves show a symmetric current characteristic with the applied voltage (see ESI 7 † ) and behave similar to expected I ( V ) curves in MOS structures. 73,74 In macroscopic tunnel junction measurements, direct tunneling was observed by Singh-Bhalla et al 75 for the lower voltage regime, which transitioned into Fowler–Nordheim tunneling for the higher voltage regime when similar LAO thicknesses were used. Analyzing the I ( V ) characteristic (see ESI 7 † ), revealed a similar behavior for low voltages, however, judging from the I ( V ) slope at higher voltages, the most likely conduction mechanism is Poole–Frenkel emission (trap-assisted tunneling) for the used setup and samples.…”