摘要:
A bottom spin-valve GMR sensor has been fabricated that has ultra-thin layers of high density and smoothness. In addition, these layers are inherently furnished with sub-monolayer thick oxygen surfactant layers. The sensor is fabricated using a method in which the layers are sputtered in a mixture of Ar and O2. A particularly novel feature of the method is the use of a sputtering chamber with an ultra-low base pressure and correspondingly ultra-low pressure mixtures of Ar and O2 sputtering gas (
摘要:
A STT-RAM MTJ is disclosed with a MgO tunnel barrier formed by natural oxidation and containing an oxygen surfactant layer to form a more uniform MgO layer and lower breakdown distribution percent. A CoFeB/NCC/CoFeB composite free layer with a middle nanocurrent channel layer minimizes Jc0 while enabling thermal stability, write voltage, read voltage, and Hc values that satisfy 64 Mb design requirements. The NCC layer has RM grains in an insulator matrix where R is Co, Fe, or Ni, and M is a metal such as Si or Al. NCC thickness is maintained around the minimum RM grain size to avoid RM granules not having sufficient diameter to bridge the distance between upper and lower CoFeB layers. A second NCC layer and third CoFeB layer may be included in the free layer or a second NCC layer may be inserted below the Ru capping layer.
摘要:
An STT-MTJ MRAM cell utilizes transfer of spin angular momentum as a mechanism for changing the magnetic moment direction of a free layer. The cell includes an IrMn pinning layer, a SyAP pinned layer, a naturally oxidized, crystalline MgO tunneling barrier layer that is formed on an Ar-ion plasma smoothed surface of the pinned layer and, in one embodiment, a composite tri-layer free layer that comprises an amorphous layer of Co60Fe20B20 of approximately 20 angstroms thickness formed between two crystalline layers of Fe of 3 and 6 angstroms thickness respectively. The free layer is characterized by a low Gilbert damping factor and by very strong polarizing action on conduction electrons. The resulting cell has a low critical current, a high dR/R and a plurality of such cells will exhibit a low variation of both resistance and pinned layer magnetization angular dispersion.
摘要:
An MTJ MRAM cell and its method of formation are described. The cell includes a composite free layer having the general form (Ni88Fe12)1-xCo100x—Ni92Fe8 with x between 0.05 and 0.1 that provides low magnetization and negative magnetostriction. The magnetostriction can be tuned to a low value by a multilayer capping layer that includes a positive magnetostriction layer of NiFeHf(15%). When this cell forms an MRAM array, it contributes to a TMR≧26%, a TMR/Rp—cov≧15.5 and a high AQF (array quality factor) for write operations.
摘要:
An MRAM is disclosed that has a MTJ comprised of a ferromagnetic layer with a magnetization direction along a first axis, a super-paramagnetic (SP) free layer, and an insulating layer formed therebetween. The SP free layer has a remnant magnetization that is substantially zero in the absence of an external field, and in which magnetization is roughly proportional to an external field until reaching a saturation value. In one embodiment, a separate storage layer is formed above, below, or adjacent to the MTJ and has uniaxial anisotropy with a magnetization direction along its easy axis which parallels the first axis. In a second embodiment, the storage layer is formed on a non-magnetic conducting spacer layer within the MTJ and is patterned simultaneously with the MTJ. The SP free layer may be multiple layers or laminated layers of CoFeB. The storage layer may have a SyAP configuration and a laminated structure.
摘要:
Two embodiments of a GMR sensor of the bottom spin valve (BSV) spin filter spin valve (SFSV) type are provided, together with methods for their fabrication. In one embodiment, the sensor has an ultra thin (
摘要:
Patterned, longitudinally and transversely antiferromagnetically exchange biased GMR sensors are provided which have narrow effective trackwidths and reduced side reading. The exchange biasing significantly reduces signals produced by the portion of the ferromagnetic free layer that is underneath the conducting leads while still providing a strong pinning field to maintain sensor stability. In the case of the transversely biased sensor, the magnetization of the free and biasing layers in the same direction as the pinned layer simplifies the fabrication process and permits the formation of thinner leads by eliminating the necessity for current shunting.
摘要:
Two embodiments of a GMR sensor of the bottom spin valve (BSV) spin filter spin valve (SFSV) type are provided together with methods for their fabrication. In each embodiment the sensor includes an in-situ naturally oxidized specularly reflecting layer (NOL) which is a more uniform and dense layer than such layers formed by high temperature annealing or reactive-ion etching. In one embodiment, the sensor has an ultra thin composite free layer and a high-conductance layer (HCL), providing high output and low coercivity. In a second embodiment, along with the same NOL, the sensor has a laminated free layer which includes a non-magnetic conductive layer, which also provides high output and low coercivity. The sensors are capable of reading densities exceeding 60 Gb/in2.
摘要翻译:底部自旋阀(BSV)旋转过滤器自旋阀(SFSV)型的GMR传感器的两个实施例与其制造方法一起提供。 在每个实施例中,传感器包括原位自然氧化的镜面反射层(NOL),其比通过高温退火或反应离子蚀刻形成的这种层更均匀和致密的层。 在一个实施例中,传感器具有超薄复合自由层和高电导层(HCL),提供高输出和低矫顽力。 在第二实施例中,与相同的NOL一起,传感器具有包括非磁性导电层的层叠自由层,其也提供高输出和低矫顽力。 这些传感器能够读取超过60Gb / in <2>的密度。
摘要:
A high performance MTJ, and a process for manufacturing it, are described. A capping layer of NiFeHf is used to getter oxygen out of the free layer, thereby increasing the sharpness of the free layer-tunneling layer interface. The free layer comprises two NiFe layers whose magnetostriction constants are of opposite sign, thereby largely canceling one another.