A programmable metallization
cell ("PMC") comprises a
fast ion conductor such as a
chalcogenide-
metal ion and a plurality of electrodes (e.g., an
anode and a
cathode) disposed at the surface of the
fast ion conductor and spaced a
set distance apart from each other. Preferably, the
fast ion conductor comprises a
chalcogenide with Group IB or Group IIB metals, the
anode comprises silver, and the
cathode comprises aluminum or other conductor. When a
voltage is applied to the
anode and the
cathode, a non-volatile
metal dendrite grows from the cathode along the surface of the fast
ion conductor towards the anode. The growth rate of the
dendrite is a function of the applied
voltage and time. The growth of the
dendrite may be stopped by removing the
voltage and the dendrite may be retracted by reversing the
voltage polarity at the anode and cathode. Changes in the length of the dendrite affect the resistance and
capacitance of the PMC. The PMC may be incorporated into a variety of technologies such as memory devices, programmable
resistor /
capacitor devices, optical devices, sensors, and the like. Electrodes additional to the cathode and anode can be provided to serve as outputs or additional outputs of the devices in sensing electrical characteristics which are dependent upon the extent of the dendrite.