Design rules for threshold switches based on a field triggered thermal runaway mechanism

Abstract

We investigate a new type of threshold switching devices, which is based on a purely electronic phenomena. These threshold switches are polarity independent and switch abruptly from a high resistive state to a low resistive state at a threshold voltage. The device stays in this low resistive state as long as a high voltage drops over the device. When the voltage is reduced, the low resistive state is lost and the device switches back to the initial high resistive state. This makes these threshold switches highly interesting as selector elements for resistive switching memory concepts, based on device arrays, which are the prerequisite for new applications like logic-in-memory concepts. The threshold switching considered here is based on a combination of a Poole---Frenkel conduction mechanism and Joule heating. Hence, it is not strongly restricted to specific materials rather it is connected to the physical quantities of the Poole---Frenkel conduction mechanism and the thermal conductance. This enables to design the threshold switch to its application requirements by adjusting the relevant physical material properties or designing the device geometry. Here we present a theoretical study, which tackles the influence of several material properties and the device design. From this simulation model the impact on technical important figures of merits is determined, such as the threshold switching voltage and the selectivity.