Magnetic random access memory with perpendicular interfacial anisotropy

摘要

The present invention is directed to an MRAM element comprising a magnetic free layer structure and a magnetic reference layer structure with an insulating tunnel junction layer interposed therebetween. The magnetic free layer structure has a variable magnetization direction substantially perpendicular to the layer plane thereof. The magnetic reference layer structure includes a first magnetic reference layer formed adjacent to the insulating tunnel junction layer and a second magnetic reference layer separated from the first magnetic reference layer by a first non-magnetic perpendicular enhancement layer. The first and second magnetic reference layers have a first fixed magnetization direction substantially perpendicular to the layer plane thereof. The second magnetic reference layer has a multilayer structure comprising a first magnetic reference sublayer formed adjacent to the first non-magnetic perpendicular enhancement layer and a second magnetic reference sublayer separated from the first magnetic reference sublayer by an intermediate metallic layer.

主权项

1. A magnetic random access memory (MRAM) device comprising a plurality of memory elements, each of said memory element including a magnetic tunnel junction (MTJ) structure in between a non-magnetic seed layer and a non-magnetic cap layer, said MTJ structure comprising a magnetic free layer structure and a magnetic reference layer structure with an insulating tunnel junction layer interposed therebetween, wherein said magnetic free layer structure includes a first magnetic free layer formed adjacent to said insulating tunnel junction layer and a second magnetic free layer separated from said first magnetic free layer by a second non-magnetic perpendicular enhancement layer (PEL), said first and second magnetic free layers having respectively first and second variable magnetization directions that are substantially perpendicular to layer planes thereof and are oriented in a same direction, said magnetic reference layer structure includes a first magnetic reference layer formed adjacent to said insulating tunnel junction layer and a second magnetic reference layer separated from said first magnetic reference layer by a first non-magnetic perpendicular enhancement layer, said first and second magnetic reference layers having a first fixed magnetization direction substantially perpendicular to layer planes thereof, said second magnetic reference layer having a multilayer structure formed by interleaving two different types of materials with at least one of said two different types being magnetic.