Threshold switching characteristics

The paper describes experiments on thresholds switches, based on a multicomponent chalcogenide glass (Te₄₀As₃₅Ge₇Si₁₈) of about 1 μm thickness, and pyrolytic graphite electrodes. The results demonstrate that “forming processes” (of presumably electrolytic character) in the off-state affect only the contact area which is not engaged in filamentary conduction when the switch is in the on-state. The detailed on-state characteristics are shown to depend on (a) the maximum on-current reached during the switching event, and (b) the rate of voltage change, and this is why depend on the external series resistance. Forming processes in the on-state must arise from a very different mechanism, and the operational reality of the minimum holding current has been established. The resultsfavor non-thermal interpretations of threshold switching as such, albeit inevitably with certain “thermal overtones”.