Aluminum-oxide tunnel barriers with high field endurance

We have measured transport properties of all-metallic tunnel junctions, fabricated using rf-plasma-grown aluminum oxide layers and rapid thermal postannealing, in particular, their endurance in electric fields in excess of 10 MV/cm. The results indicate that such junctions may combine high-field endurance (corresponding to at least 1010 write/erase cycles in floating-gate memories) and high current density (corresponding to 30 ns scale write/erase time) at high voltages, with very low conductance (corresponding to ∼0.1 s scale retention time) at low voltages. We discuss the improvements necessary for the use of such junctions in advanced floating-gate memories.