Magnetic Memory Device With Boron-Doped Conductive Layer
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Solution Overview
Problem
Magnetic memory devices face challenges in reducing the write current, which affects their efficiency and performance due to issues like magnetic dead layers and anisotropic magnetic fields.
Innovation Solution
Incorporating a conductive layer with specific regions, including boron, to optimize the thickness and composition of the second region between the first and second magnetic layers, reducing the magnetic dead layer and enhancing the spin Hall effect, thereby lowering the write current.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If a conventional conductive layer is used without boron doping, then the device structure is simpler, but the write current density is higher and magnetic dead layer thickness increases
Solution Approach 1:
The conductive layer is divided into three regions with different boron concentrations: a first region without boron, a second region with high boron concentration adjacent to the magnetic layer, and a third region with intermediate boron concentration. This local quality variation optimizes the spin Hall effect and reduces magnetic dead layer thickness at the interface while maintaining overall device functionality
Solution Approach 2:
The conductive layer uses a composite structure combining multiple materials (Ta, W, Mo, Hf, Nb, TaN, WN, MoN, HfN, NbN) with varying boron concentrations in different regions. This composite approach allows simultaneous optimization of electrical conductivity, spin Hall effect, and magnetic layer interface properties
2Reliability
If the second region with boron is made thicker, then the spin Hall effect is enhanced, but the magnetic dead layer thickness increases
Solution Approach 1:
The thickness of the second region with boron is precisely controlled within 0.5-5 nm, and the boron concentration is optimized at 10-50 atomic percent. These parameter changes maximize the spin Hall effect while minimizing magnetic dead layer formation by balancing the interface quality and magnetic coupling
3Power
If boron concentration in the second region is increased, then the spin Hall angle is enhanced, but magnetic dead layer forms more readily
Solution Approach 1:
Different boron concentrations are applied in different regions: the second region has high boron concentration (10-50 at%) to maximize spin Hall angle, while the first region has no boron to prevent magnetic dead layer formation. This spatial differentiation of material quality resolves the contradiction between enhancing spin Hall effect and preventing magnetic dead layer
4Use of energy by moving object
If the conductive layer is made more complex with multiple regions, then write current is reduced, but manufacturing precision requirements increase
Solution Approach 1:
The conductive layer is segmented into three distinct regions with different boron concentrations, each deposited in separate sequential steps. This segmentation allows independent optimization of each region's properties while maintaining manufacturability through standard multi-step deposition processes
Solution Approach 2:
The first region without boron is deposited first to establish a clean interface with the magnetic layer, preventing magnetic dead layer formation. Subsequent deposition of boron-containing regions then enhances the spin Hall effect without compromising the already-formed interface quality
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The solution effectively reduces the write current density and magnetic dead layer thickness, improving the magnetic memory device's performance by enhancing the spin Hall angle and perpendicular anisotropic magnetic field, leading to more efficient data storage.
Implementation Method 1
enhancing the spin Hall effect, thereby lowering the write current
Implementation Method 2
enhancing the spin Hall angle and perpendicular anisotropic magnetic field
Data Source
AI summary
According to one embodiment, a magnetic memory device includes a conductive layer, a first magnetic layer, a second magnetic layer, a first nonmagnetic layer, and a controller. The conductive layer includes a first portion, a second portion, and a third portion between the first and second portions. The first magnetic layer is separated from the third portion. The second magnetic layer is provided between the third portion and the first magnetic layer. The first nonmagnetic layer is provided between the first and second magnetic layers. The controller is electrically connected to the first and second portions. The third portion includes a first region and a second region. The second region is provided between the first region and the second magnetic layer. The controller implements a first operation of supplying a first current to the conductive layer, and a second operation of supplying a second current to the conductive layer.