According to one embodiment, a method includes forming a first insulative layer above a bottom surface of a groove and along inner sidewalls thereof, forming a source line layer within the groove of the substrate, forming a first dielectric layer on outer sides of a middle portion of the source line layer, forming a buffer layer on outer sides of the first dielectric layer, forming a gate terminal above the source line layer, forming a gate dielectric layer between the source line layer and the gate terminal and on outer sides of the lower portion of the gate terminal, forming a drain terminal including strained Si on outer sides of the first dielectric layer, and forming a relaxed buffer layer on outer sides of the upper portion of the source line layer and outer sides of the drain terminal, with the gate terminal extending beyond the relaxed buffer layer thickness.

The present disclosure generally relates to a Wheatstone bridge that has four resistors. Each resistor includes a plurality of TMR structures. Two resistors have identical TMR structures. The remaining two resistors also have identical TMR structures, though the TMR structures are different from the other two resistors. Additionally, the two resistors that have identical TMR structures have a different amount of TMR structures as compared to the remaining two resistors that have identical TMR structures. Therefore, the working bias field for the Wheatstone bridge is non-zero.

Encapsulation topography-assisted techniques for forming self-aligned top contacts in MRAM devices are provided. In one aspect, a method for forming an MRAM device includes: forming MTJs on interconnects embedded in a first dielectric; depositing an encapsulation layer over the MTJs; burying the MTJs in a second dielectric; patterning a trench in the second dielectric over the MTJs exposing the encapsulation layer over tops of the MTJs which creates a topography at the trench bottom; forming a metal line in the trench over the topography; recessing the metal line which breaks up the metal line into segments separated by exposed peaks of the encapsulation layer; recessing the exposed peaks of the encapsulation layer to form recesses at the tops of the MTJs; and forming self-aligned contacts in the recesses. An MRAM device is also provided.

A magnetic tunnel junction (MTJ) is disclosed wherein a nitride diffusion barrier (NDB) has a L2/L1/NL or NL/L1/L2 configuration wherein NL is a metal nitride or metal oxynitride layer, L2 blocks oxygen diffusion from an adjoining Hk enhancing layer, and L1 prevents nitrogen diffusion from NL to the free layer (FL) thereby enhancing magnetoresistive ratio and FL thermal stability, and minimizing resistance x area product for the MTJ. NL is the uppermost layer in a bottom spin valve configuration, or is formed on a seed layer in a top spin valve configuration such that L2 and L1 are always between NL and the FL or pinned layer, respectively. In other embodiments, one or both of L1 and L2 are partially oxidized. Moreover, either L2 or L1 may be omitted when the other of L1 and L2 is partially oxidized. A spacer between the FL and L2 is optional.

A magnetic memory structure employs electric-field controlled interlayer exchange coupling between a free magnetic layer and a fixed magnetic layer to switch a magnetization direction. The magnetic layers are separated by a spacer layer disposed between two oxide layers. The spacer layer exhibits a large IEC while the oxide layers provide tunnel barriers, forming a quantum-well between the magnetic layers with discrete energy states above the equilibrium Fermi level. When an electric field is applied across the structure, the tunnel barriers become transparent at discrete energy states via a resonant tunneling phenomenon. The wave functions of the two magnets then can interact and interfere to provide a sizable IEC. IEC can control the magnetization direction of the free magnetic layer relative to the magnetization direction of the fixed magnetic layer depending on the sign of the IEC, induced by a magnitude of the applied electric field above a threshold value.

Embodiments of the disclosure provide methods and apparatus for fabricating magnetic tunnel junction (MTJ) structures on a substrate for MRAM applications. In one embodiment, a magnetic tunnel junction (MTJ) device structure includes a junction structure disposed on a substrate, the junction structure comprising a first ferromagnetic layer and a second ferromagnetic layer sandwiching a tunneling barrier layer, a dielectric capping layer disposed on the junction structure, a metal capping layer disposed on the junction structure, and a top buffer layer disposed on the metal capping layer.

A spin-transfer torque (STT) magnetoresistive memory device includes a first electrode, a second electrode, and a magnetic tunnel junction located between the first electrode and the second electrode. The magnetic tunnel junpction includes a reference layer having a fixed magnetization direction, a free layer stack, and a nonmagnetic tunnel barrier layer located between the reference layer and the free layer stack. The free layer stack has a total thickness of less than 2 nm, and contains in order, a proximal ferromagnetic layer located proximal to the nonmagnetic tunnel barrier layer, a first non-magnetic metal sub-monolayer, an intermediate ferromagnetic layer, a second non-magnetic metal sub-monolayer, and a distal ferromagnetic layer.

A memory device including bit lines, auxiliary lines, selectors, and memory cells is provided. The word lines are intersected with the bit lines. The auxiliary lines are disposed between the word lines and the of bit lines. The selectors are inserted between the bit lines and the auxiliary lines. The memory cells are inserted between the word lines and the auxiliary lines.

Methods and apparatus for forming a magnetic tunnel element are provided herein. A method of forming a magnetic tunnel element includes: depositing a magnetic layer atop a cobalt-chromium seed layer; and depositing a tunnel layer atop the magnetic layer to form a magnetic tunnel element, wherein the magnetic tunnel element has a TMR greater than 100. For example, a cobalt/platinum material or one or more layers thereof may be deposited directly atop a cobalt-chromium seed layer to produce improved devices.

Each memory cell in an array includes a vertical stack that comprises a bottom electrode, a memory element, and a top electrode. An etch stop dielectric layer is formed over the array of memory cells. A first dielectric matrix layer is formed over the etch stop dielectric layer. The top surface of the first dielectric matrix layer is raised in a memory array region relative to a logic region due to topography. The first dielectric matrix layer is planarized by performing a chemical mechanical planarization process using top portions of the etch stop dielectric layer. A second dielectric matrix layer is formed over the first dielectric matrix layer. Metallic cell contact structures are formed through the second dielectric matrix layer on a respective subset of the top electrodes over vertically protruding portions of the etch stop dielectric layer that laterally surround the array of vertical stacks.