ON-state evolution in lateral and vertical VO2 threshold switching devices.

We report the results of finite element simulations of the ON state characteristic of VO2-based threshold switching devices and compare the results with experimental data. The model is based on thermally induced threshold switching (thermal runaway) and successfully reproduces the I-V characteristics showing the formation and growth of the conductive filament in the ON state. Furthermore, we compare the I-V characteristics for two VO2 films with different electrical conductivities in the insulating and metallic phases as well as those based on TaO x and NbO x functional layers.