Abstract:
A MTJ is sensed by applying a first reference current, first programming the MTJ to a first value using the first reference current, detecting the resistance of the first programmed MTJ, and if the detected resistance is above a first reference resistance, declaring the MTJ to be at a first state. Otherwise, upon determining if the detected resistance is below a second reference resistance, declaring the MTJ to be at a second state. In some cases, applying a second reference current through the MTJ and second programming the MTJ to a second value using the second reference current. Detecting the resistance of the second programmed MTJ and in some cases, declaring the MTJ to be at the second state, and in other cases, declaring the MTJ to be at the first state and programming the MTJ to the second state.
Abstract:
Methods and structures are described to reduce metallic redeposition material in the memory cells, such as MTJ cells, during pillar etching. One embodiment forms metal studs on top of the landing pads in a dielectric layer that otherwise covers the exposed metal surfaces on the wafer. Another embodiment patterns the MTJ and bottom electrode separately. The bottom electrode mask then covers metal under the bottom electrode. Another embodiment divides the pillar etching process into two phases. The first phase etches down to the lower magnetic layer, then the sidewalls of the barrier layer are covered with a dielectric material which is then vertically etched. The second phase of the etching then patterns the remaining layers. Another embodiment uses a hard mask above the top electrode to etch the MTJ pillar until near the end point of the bottom electrode, deposits a dielectric, then vertically etches the remaining bottom electrode.
Abstract:
A non-volatile magnetic memory element includes a number of layers one of which is a free layer which is graded. The graded free layer may include various elements with each element having a different anisotropy or it may include nonmagnetic compounds and magnetic regions with the non-magnetic compounds forming graded contents forming a unique shape such as cone shaped, diamond shaped or other shapes and whose thickness is based on the reactivity of the magnetic compound.
Abstract:
A non-volatile magnetic memory element includes a number of layers one of which is a free layer which is graded. The graded free layer may include various elements with each element having a different anisotropy or it may include nonmagnetic compounds and magnetic regions with the non-magnetic compounds forming graded contents forming a unique shape such as cone shaped, diamond shaped or other shapes and whose thickness is based on the reactivity of the magnetic compound.
Abstract:
A non-volatile magnetic memory element includes a number of layers one of which is a free layer which is graded. The graded free layer may include various elements with each element having a different anisotropy or it may include nonmagnetic compounds and magnetic regions with the non-magnetic compounds forming graded contents forming a unique shape such as cone shaped, diamond shaped or other shapes and whose thickness is based on the reactivity of the magnetic compound.
Abstract:
A non-volatile magnetic memory element includes a number of layers one of which is a free layer which is graded. The graded free layer may include various elements with each element having a different anisotropy or it may include nonmagnetic compounds and magnetic regions with the non-magnetic compounds forming graded contents forming a unique shape such as cone shaped, diamond shaped or other shapes and whose thickness is based on the reactivity of the magnetic compound.
Abstract:
A non-uniform switching based non-volatile magnetic memory element includes a fixed layer, a barrier layer formed on top of the fixed layer, a first free layer formed on top of the barrier layer, a non-uniform switching layer (NSL) formed on top of the first free layer, and a second free layer formed on top of the non-uniform switching layer. Switching current is applied, in a direction that is substantially perpendicular to the fixed layer, barrier layer, first free layer, non-uniform switching layer and the second free layer causing switching between states of the first free layer, second free layer and non-uniform switching layer with substantially reduced switching current.
Abstract:
A non-volatile current-switching magnetic memory element includes a bottom electrode, a pinning layer formed on top of the bottom electrode, and a fixed layer formed on top of the pinning layer. The memory element further includes a tunnel layer formed on top of the pinning layer, a first free layer formed on top of the tunnel layer, a granular film layer formed on top of the free layer, a second free layer formed on top of the granular film layer, a cap layer formed on top of the second layer and a top electrode formed on top of the cap layer.
Abstract:
A flash-RAM memory includes non-volatile random access memory (RAM) formed on a monolithic die and non-volatile page-mode memory formed on top of the non-volatile RAM, the non-volatile page-mode memory and the non-volatile RAM reside on the monolithic die. The non-volatile RAM is formed of stacks of magnetic memory cells arranged in three-dimensional form for higher density and lower costs.
Abstract:
A multi-state current-switching magnetic memory element has a magnetic tunneling junction (MTJ), for storing more than one bit of information. The MTJ includes a fixed layer, a barrier layer, and a non-uniform free layer. In one embodiment, having 2 bits per cell, when one of four different levels of current is applied to the memory element, the applied current causes the non-uniform free layer of the MTJ to switch to one of four different magnetic states. The broad switching current distribution of the MTJ is a result of the broad grain size distribution of the non-uniform free layer.