Electronic properties of Cu/SiO2/Cu structures at different temperatures

In this experimental work, some electronic properties of vacuum evaporated Cu/SiO₂/Cu structures such as circuiting I_c and emission I_e currents versus the applied voltage, electron attenuation lengths in both copper and SiO₂ layers and the role of the latter layers have been investigated. Experimental results show that these devices undergo an electroforming process leading to resistivity decrease of several orders of magnitude along with a negative resistance region in their current–voltage characteristics. By decreasing the temperature, both I_c and I_e are decreased and at low temperatures the negative resistance region disappears completely. Electron attenuation lengths are measured between 6 and 14 V for copper and SiO₂ layers and their significance are discussed on the base of electron-impurity and electron-defect scatterings. The conduction mechanism is also discussed on the base of a filamentary model.