Structures and formation methods of a semiconductor structure are provided. The semiconductor structure includes an insulating layer covering a device region and an alignment mark region of a semiconductor substrate. A conductive feature is formed in the insulating layer and corresponds to the device region. An alignment mark structure is formed in the first insulating layer and corresponds to the alignment mark region. The alignment mark structure includes a first conductive layer, a second conductive layer covering the first conductive layer, and a first magnetic tunnel junction (MTJ) stack layer covering the second conductive layer. The first conductive layer and the conductive feature are made of the same material.

A method for fabricating a magnetic random access memory (MRAM) device includes the steps of first forming a magnetic tunneling junction (MTJ) stack on a substrate, forming a first top electrode on the MTJ stack, and then forming a second top electrode on the first top electrode. Preferably, the first top electrode includes a gradient concentration while the second top electrode includes a non-gradient concentration.

Apparatuses, systems, and methods are disclosed for magnetoresistive random access memory. A magnetic tunnel junction (MTJ) for storing data may include a reference layer. A free layer of an MTJ may be separated from a reference layer by a barrier layer. A free layer may be configured such that one or more resistance states for an MTJ correspond to one or more positions of a magnetic domain wall within the free layer. A domain stabilization layer may be coupled to a portion of a free layer, and may be configured to prevent migration of a domain wall into the portion of the free layer.

The present disclosure provides a domain wall magnetic tunnel junction device. Integration of input spikes pushes a domain wall within a ferromagnetic track toward a magnetic tunnel junction (MTJ). An energy gradient within the track pushes the domain wall away from the MTJ by leaking accumulated energy from the input spikes. If the integrated input spikes exceed the energy leak of the gradient within a specified time period, the domain wall reaches the MTJ and reverses its resistance, producing an output spike. The leaking energy gradient can be created by a magnetic field, a trapezoidal shape of the ferromagnetic track, or nonuniform material properties in the ferromagnetic track.

One illustrative method disclosed herein includes forming at least one first layer of insulating material above an upper surface of a top electrode of a memory cell, forming a patterned etch stop layer above the at least one first layer of insulating material, wherein the patterned etch stop layer has an opening that is positioned vertically above at least a portion of the upper surface of the top electrode and forming at least one second layer of insulating material above an upper surface of the etch stop layer. The method also includes forming a conductive contact opening that extends through the etch stop layer to expose at least a portion of the upper surface of the top electrode and forming a conductive contact structure in the conductive contact opening, wherein the conductive contact structure is conductively coupled to the upper surface of the top electrode.

A semiconductor device may be provided including a first series portion and a second series portion electrically connected in parallel with the first series portion. The first series portion may include a first MTJ stack and a first resistive element electrically connected in series. The second series portion may include a second MTJ stack and a second resistive element electrically connected in series. The first resistive element may include a third MTJ stack and the second resistive element may include a fourth MTJ stack. The first, second, third, and fourth MTJ stacks may include a same number of layers, which may include a fixed layer, a free layer, and a tunnelling barrier layer between the fixed layer and the free layer. Alternatively, the first resistive element may include a first transistor and the second resistive element may include a second transistor.

A memory device includes a bottom electrode, a tunneling junction disposed over the bottom electrode, and a top electrode disposed over the tunneling junction. The top electrode includes a first top electrode layer and a second top electrode layer above the first top electrode layer. The first and second top electrode layers include different material compositions. The first top electrode layer is thinner than the tunneling junction, and the second top electrode layer is thicker than the tunneling junction.

A semiconductor device includes a substrate, a first magnetic tunnel junction (MTJ) structure, a second MTJ structure, and an interconnection structure. The first MTJ structure, the second MTJ structure, and the interconnection structure are disposed on the substrate. The interconnection structure is located between the first MTJ structure and the second MTJ structure in a first horizontal direction, and the interconnection structure includes a first metal interconnection and a second metal interconnection. The second metal interconnection is disposed on and contacts the first metal interconnection.

A magnetic domain wall movement element includes a magnetic recording layer which includes a ferromagnetic material; a non-magnetic layer which is laminated on the magnetic recording layer; and a magnetization reference layer which is laminated on the non-magnetic layer, in which the magnetic recording layer has a first ferromagnetic layer, a spacer layer, and a second ferromagnetic layer in order from the non-magnetic layer, a magnetization of the first ferromagnetic layer and a magnetization of the second ferromagnetic layer are antiferromagnetically coupled, and an electrical resistivity of the first ferromagnetic layer is higher than the electrical resistivity of the second ferromagnetic layer.

A method of forming a semiconductor memory device is disclosed. A top electrode layer is formed on the MTJ stack layer. A patterned buffer layer is formed to cover only the logic circuit region. A hard mask layer is formed on the top electrode layer and the patterned buffer layer. A patterned resist layer is formed on the hard mask layer. A first etching process is performed to etch the hard mask layer and the top electrode layer not covered by the patterned resist layer in the memory region and the hard mask layer, the patterned buffer layer and the top electrode layer in the logic circuit region, thereby forming a top electrode on the MTJ stack layer in the memory region and a remaining top electrode layer covering only the logic circuit region on the MTJ stack layer.