Effect of on-line flash anneal on aging properties of NDRO multilayer plated wire

Aging properties of the plated wire stabilized by on-line flash annealing for 6 seconds were investigated and a sufficient stabilizing effect has been obtained. The wire has a multilayer construction including three Permalloy layers and two Ni-Co hard layers, and has good nondestructive readout (NDRO) properties, Aging was accelerated by dc and pulsed hard-axis fields at temperatures between 50°C and 150°C. The largest change has been found in which is the upper limit of the digit current margin. Provided that lifetime is the time required for the 10-percent degradation, a typical wire has a lifetime of 100 years under the dc hard-axis field at 40°C. According to the extrapolation from the lifetime distribution of the wires, the first failure bit in a million bits operating under de field at 40°C is predicted after 20 years. Since in actual memory devices the wires are driven by a word pulse field instead of a dc field, much longer time will be required before the first failure.