Spin transfer torque magnetic random access memory (STTMRAM) having graded synthetic free layer

摘要

A spin transfer torque memory random access memory (STTMRAM) element is capable of switching states when electrical current is applied thereto for storing data and includes the following layers. An anti-ferromagnetic layer, a fixed layer formed on top of the anti-ferromagnetic layer, a barrier layer formed on top of the second magnetic layer of the fixed layer, and a free layer including a first magnetic layer formed on top of the barrier layer, a second magnetic layer formed on top of the first magnetic layer, a non-magnetic insulating layer formed on top of the second magnetic layer and a third magnetic layer formed on top of the non-magnetic insulating layer. A capping layer is formed on top of the non-magnetic insulating layer.

主权项

1. A spin transfer torque random access memory (STTMRAM) element capable of switching states when electrical current is applied thereto for storing data, the STTMRAM element comprising:
an anti-ferromagnetic layer; a fixed layer formed on top of the anti-ferromagnetic layer, the fixed layer comprising:
a first fixed magnetic layer having a first fixed magnetic orientation substantially parallel to the layer plane thereof; anda second fixed magnetic layer having a second fixed magnetic orientation substantially parallel to the layer plane thereof; a barrier layer formed directly on top of the second fixed magnetic layer; a free layer including:
a first free magnetic layer formed directly on top of the barrier layer and having associated therewith a first saturation magnetization (Ms), the first free magnetic layer having a first switchable magnetic orientation substantially parallel to the layer plane thereof;a second free magnetic layer formed on top of the first free magnetic layer and having associated therewith a second Ms, the second free magnetic layer having a second switchable magnetic orientation substantially parallel to the layer plane thereof;a non-magnetic insulating layer formed on top of the second free magnetic layer; anda third free magnetic layer formed on top of the non-magnetic insulating layer, the third free magnetic layer having a third switchable magnetic orientation substantially parallel to the layer plane thereof;wherein the first Ms of the first free magnetic layer is higher than the second Ms of the second free magnetic layer, the first and second switchable magnetic orientations have substantially the same direction that is substantially opposite to the third switchable magnetic orientation; and a capping layer formed directly on top of the third free magnetic layer, wherein the first fixed magnetic layer is made of a material comprising: silicon dioxide (SiO2), titanium dioxide (TiO2), tantalum oxide (Ta2O5), aluminum oxide (Al2O3), or any combination thereof.