On a current mechanism in Ta2O5 thin films

Abstract

Abstract:Electrical conduction in the temperature range of 120-370 K has been studied in sandwiched structures of Al/Ta 2 O 5 /Si. The tantalum oxide films were prepared by evaporation of tantalum on a p-Si crystal substrate, followed by oxidation at a temperature of 600˚C. The temperature-dependent current-voltage (I − V ) characteristics are explained on the basis of a phonon-assisted tunnelling model. The same explanation is given for I − V data measured on Ta 2 O 5 films by other investigators. From the comparison of experimental data with theory the density of states in the interface layer is derived and the electron-phonon interaction constant is assessed.

Gate oxide thickness dependence of the leakage current mechanism in Ru/Ta2O5/SiON/Si structures

“…Trap level extracted from the FE plot is lower than that determined from the zero electric field trap barrier height extrapolation for PFE. This behaviour indicates that the conduction mechanism in the MOS capacitor with 3.5 < t ox < 10 nm is governed by TTT, however, other mechanisms such as phonon-assisted tunnelling can also contribute [17].…”

“…Leakage current mechanisms in metal-oxidesemiconductor (MOS) structures with Ta 2 O 5 have been extensively studied and also reviewed in the last decade [6,[9][10][11][12][13][14][15][16][17]. In most of the cases, Schottky emission or hopping has been reported as a dominant mechanism for low oxide electric fields [9,11], Poole-Frenkel emission (PFE) in the moderate electric field [6, 9-13, 15, 16], and in some cases the Fowler-Nordheim conduction mechanism has been observed for high electric fields in the oxide [9].…”

“…Direct tunnelling (DT) or trap-assisted tunnelling (TT) across the ultrathin SiO 2 -or a SiON-like IFL has been assumed [12,15]. However, in the recent papers, Schottky emission [14] and phonon-assisted tunnelling [17] have been reported to govern the leakage current through the Ta 2 O 5 grown by MOCVD and oxidation of evaporated Ta, respectively. Spassov et al [16] also pointed out that a gate electrode deposition technique influences the dominant conduction mechanism in rf-sputtered Ta 2 O 5 .…”

Variable range hopping and/or phonon-assisted tunneling mechanism of electronic transport in polymers and carbon nanotubes

“…The object of the PhAT investigation has also been extensively studied in our and co-workers' papers: for polymers films [5,11,71], for MEH-PPV diodes [6], polyacetylene nanofibers [7], some oxide nanowires or films [8,10], carbon nanotube networks [12,13], graphene nanoribbons and graphene oxides [57], and polydiacetylene crystals [72]. Some authors have currently applied the PhAT model that we propose and Eq.…”

“…However, the focus of attention here was assigned to variable range hopping (VRH) [3,4] as the dominant transport mechanism in these materials, and the model is based only on the temperature dependences of conductivity. A number of articles have appeared in the last decade where the electrical-field induced phononassisted tunneling (PhAT) model has been suggested to describe the temperature dependent conductivity in polymers [5][6][7], inorganic materials [8][9][10][11] and carbon nanotubes [12,13]. The said PhAT model is based on the quantum-mechanical theory, and it can properly explain not only the temperature dependences of conductivity, but also the temperature-dependent current-voltage characteristics in a wide range of temperatures and electric field strengths.…”