Magnetoresistive memories - analogies with ferroelectrics

Abstract

Both Honeywell's Magnetoresistive Random Access Memory (MRAM) technology and its antecedent, a magnetoresistive memory invented by Len Schwee1, are fortunate to use common magnetic materials which are relatively stable and easy to fabricate. Magnetoresistive material properties, the MRAM cell operation (bit selection, writing and reading), general circuit strategies, and packaging are described. Analogies and comparisons with ferroelectric memory material and cell operation are discussed. Both ferroelectric memory and MRAM can fill important (and different) product niches, but both require material developments in order for them to achieve general-purpose usage: the ferroelectric material must overcome fatigue and the MRAM must overcome a small signal level. Other less significant materials developments are also needed. Once the proper material is available, a surprisingly long development cycle is needed to get products through design, process start-up, reliability tests, and (for rad hard products) radi...