Magnetic random access memory with stacked memory layers having access lines for writing and reading

Abstract

A multiple-memory-layer magnetic random access memory (MRAM) has multiple memory layers arranged as pairs and stacked on a substrate. The first memory layer in the pair comprises a plurality of rows of memory cells located between electrically conductive access lines, and the second memory layer in the pair is substantially identical to the first memory layer, but is rotated about an axis perpendicular to the substrate so that the access lines and memory cell rows in one memory layer of the pair are orthogonal to their counterpart lines and rows in the other memory layer. The memory cells in each layer are aligned vertically (perpendicular to the substrate) with the memory cells in the other layer, with the vertically aligned memory cells forming memory cell columns that extend perpendicularly from the substrate. Each memory cell column has an electrical switch between the lowermost memory cell and the substrate.