US Patent 7683447 MRAM device with continuous MTJ tunnel layers

A method for fabricating a magnetoresistive random access memory (MRAM) device having a plurality of memory cells includes: forming a fixed magnetic layer having magnetic moments fixed in a predetermined direction; forming a tunnel layer over the fixed magnetic layer; forming a free magnetic layer, having magnetic moments aligned in a direction that is adjustable by applying an electromagnetic field, over the tunnel layer; forming a hard mask on the free magnetic layer partially covering the free magnetic layer; and unmagnetizing portions of the free magnetic layer uncovered by the hard mask for defining one or more magnetic tunnel junction (MTJ) units.