A study of electroforming processes at metal-tin selenide interfaces

The physical changes produced by electroforming and leading to bistable memory switching were investigated for metal, Sn-Se semiconductor structures. Evaporated aluminum contacts on crystalline Sn-Se were initially ohmic but became rectifying with annealing. Identical isothermal structures exhibited a Schottky barrier with polarity-dependent memory switching when subjected to an electroforming process. The electroformed samples gave superior rectifying properties to those isothermally processed. The degradation of the ohmic contact in the equilibrium process was shown to result from the recrystallization of Sn in Al to the solid solubility limits. The nonequilibrium process forces a slight deviation from stoichiometry in a very short time period with little power producing cyclic polarity-dependent memory switching.