A model for the on state of amorphous chalcogenide threshold switches

摘要

A detailed isothermal model of the on state of amorphous chalcogenide threshold switches is developed. Steady‐state carrier generation and recombination processes are discussed and estimated, and the carrier distributions in the radial direction of the conducting filament are calculated under the assumption that there are no axial variations. Simulations of dynamic decay of the filament after the sustaining voltage is removed are used to calculate both the maximum interruption time before reswitching is necessary and the time dependence of the device resistance during decay as functions of the on‐state operating point. Good agreement with experiment is obtained. The model predicts a rapid increase of device resistance in the vicinity of the maximum interruption time, and this has been confirmed by subsequent measurements. Since the rise time of the device resistance in this region is limited by the measuring circuitry and essentially independent of the on‐state operating point up to at least 100 mA, the electronic nature of both the on‐state and the recovery process is convincingly confirmed.