The change from high to low impedance of an amorphous semiconductor switch takes place at a critical field identified by the threshold voltage. The presence of conductive regions in the switching path reduces this threshold voltage. This change has been modelled by calculating the minimum resistive path length obtained when randomly placed uniform conductive spheres grow in a resistive matrix. The computed results are rather similar to those given by simply placing the spheres on a square or cubic lattice and are consistent with electrical observations in switching experiments.

No abstract

No abstract

It is shown that the statistical distribution of the lock-on time can predict the reliability of the set operation, which, in turn is influenced by the choice of reset parameters. Two modes of degradation of the threshold voltage are identified. One of these is impermanent and can be eliminated by the use of multiple reset pulses, while the other is permanent and is accelerated by the use of multiple reset pulses. An optimum of about 6 reset pulses is recommended. The impermanent mode is attributed to remnant crystalline debris while the permanent mode is attributed to electromigration.

No abstract