Magnetic random access memory having perpendicular composite reference layer

摘要

The present invention is directed to an STT-MRAM device including a plurality of magnetic tunnel junction (MTJ) memory elements. Each of the memory elements comprises a magnetic free layer structure and a magnetic reference layer structure with an insulating tunnel junction layer interposed therebetween; and a magnetic fixed layer separated from the magnetic reference layer structure by an anti-ferromagnetic coupling layer. 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 invariable magnetization direction substantially perpendicular to layer plane thereof, the magnetic fixed layer has a second invariable magnetization direction that is substantially perpendicular to layer plane thereof and is opposite to the first invariable magnetization direction.

主权项

1. A spin transfer torque magnetic random access memory (STT-MRAM) device comprising a plurality of memory elements, each of said memory elements 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; and a magnetic fixed layer separated from said magnetic reference layer structure by an anti-ferromagnetic coupling layer, wherein 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 an intermediate magnetic reference layer, said first, second, and intermediate magnetic reference layers having a first invariable magnetization direction substantially perpendicular to layer planes thereof, said magnetic fixed layer having a second invariable magnetization direction that is substantially perpendicular to a layer plane thereof and is opposite to said first invariable magnetization direction.