Three-dimensional Poole-Frenkel analytical model for carrier transport in amorphous chalcogenides

In this work, we propose a three-dimensional Poole-Frenkel (3DPF) analytical model for carrier transport in amorphous chalcogenides. 3DPF is based on the original Poole-Frenkel (PF) theory of non-interacting Coulombic traps responsible for carrier conduction in the bulk of the material. However, while in the original PF equation the device current-voltage characteristics is calculated by considering the barrier-lowering on the applied electric field direction only, in 3DPF we overcome this approximation by calculating the electronic current due to the integral effect of the Coulombic barrier shaping in three dimensions upon application of an electric field. As a consequence, 3DPF is capable to describe both the relatively-low and relatively-high electric fields regimes, while the PF equation implicitly assumes the device to be operated at high electric fields only. Thus, 3DPF features a better agreement with experimental data compared to original PF, predicting both (i) Poole-like behavior at low-fields, i.e., I proportional to sin(V), and (ii) PF-like dependence in the higher fields regime, i. e., I proportional to exp(root V), within a single coherent physical picture. The model is validated through I-V characterization on phase-change memory devices integrating amorphous Ge(2)Sb(2)T(e)5 as active material. Moreover, to address the model consistency, temperature dependence and correlations between model parameters are validated in comparison with experimental data. (C) 2013 American Institute of Physics. [http://dx.doi.org/10.1063/1.4788798]