Mechanism of GeO2 resistive switching based on the multi-phonon assisted tunneling between traps

Abstract

Model of evenly distributed traps in bulk dielectric is proposed for the resistive memory switching mechanism. Switching from high resistance to the low resistance state is explained by several-fold increase in trap concentration after the application of switching voltage. Both high and low resistance conductivities are governed by multi-phonon ionization and tunneling between neighboring traps. Thermal trap energy for oxygen vacancy and electron effective mass for crystal alpha-GeO2 were calculated using density functional theory and used for the fitting of our charge transport model of resistive memory. The model was verified on the TaN-GeO2-Ni structure with good semi-quantitative agreement with experiment. (C) 2012 American Institute of Physics. [http://dx.doi.org/10.1063/1.4729589]