Patent ID: 8080432
Filing Date: 2011-12-20
Classification: B82Y,G11C,H01F,H01L

Abstract:
1. A method for forming an Spin Torque Transfer-Magnetic Tunneling Junction (STT-MTJ) Magnetic Random Access Memory (MRAM) cell operating in a Current Perpendicular to Plane (CPP) configuration and utilizing the transfer, by torque, of conduction electron spin angular momentum to change a free layer magnetization direction, comprising: providing a substrate; forming an MTJ element on said substrate, said MTJ element comprising a vertically stacked lamination of horizontal parallel layers formed by the following methods and in the following order: forming an antiferromagnetic pinning layer of MnIr, then forming a Synthetic Anti-Parallel (SyAP) pinned layer on said pinning layer, then applying a plasma process to an exposed upper surface of said SyAP pinned layer, said plasma process producing a flat and smooth upper surface; then forming a tunneling barrier layer of MgO on said flat and smooth upper surface, said tunneling barrier layer being formed by a process comprising the sputtering of crystalline Mg and then producing its natural oxidation, whereby said tunneling barrier layer is formed directly in a crystalline state, thereby forming a crystalline layer of MgO; then forming a free layer on said crystalline layer of MgO, said free layer comprising a first layer of ferromagnetic material having a crystalline structure matching the crystalline structure of said barrier layer and producing, thereby, an enhanced effect on the scattering of polarized electrons, on which is formed a second layer of ferromagnetic material which will be rendered amorphous so as to have a low magnetic damping factor, on which formed a third layer of ferromagnetic material having a crystalline structure and an enhanced effect on the scattering of polarized electrons; then, forming a capping layer on said third ferromagnetic layer; and processing the formation at a processing temperature and in a processing magnetic field and for a processing time to render said second ferromagnetic layer amorphous and to set a magnetic moment direction in said pinned and free layers, whereby a current of conduction electrons in a vertical direction can change the free layer magnetization direction relative to a magnetization direction of said SyAP pinned layer, by the torque exerted on said free layer magnetization by electron spins characterizing said current.