SOT-MTJ Interconnect Layout for Isolated Read/Write Paths
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Current magnetoresistive random access memory (MRAM) devices face challenges such as high chip area, high cost, high power consumption, limited sensitivity, and susceptibility to temperature variations, which hinder their performance and efficiency.
Innovation Solution
The fabrication of a semiconductor device involves forming a magnetic tunneling junction (MTJ) on a substrate, surrounded by a first inter-metal dielectric layer, with a channel layer electrically connecting the MTJ to a metal interconnection, utilizing a spin orbit torque (SOT) approach to switch magnetic moments through an in-plane current, thereby isolating the read/write path and enhancing device endurance and stability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional MRAM devices are used, then data retention is achieved, but chip area, cost, and power consumption increase
Solution Approach 1:
The patent segments the current path into separate read and write paths. The write current flows through the channel layer to generate SOT for switching magnetic moments, while the read current flows through the MTJ. This segmentation allows independent optimization of each path, reducing overall chip area while maintaining data retention functionality.
Solution Approach 2:
The channel layer acts as an intermediary that converts electrical current into spin-orbit torque without directly passing through the MTJ. This mediator structure enables write operations to switch magnetic moments indirectly, reducing the area and power consumption associated with direct write current through the MTJ while preserving data retention.
2Reliability
If conventional MRAM devices are used, then data retention is achieved, but power consumption increases
Solution Approach 1:
By separating read and write current paths, the patent enables independent current routing. The write current generates SOT in the channel layer without passing through the high-resistance MTJ, significantly reducing power consumption for write operations while maintaining data retention through the MTJ's magnetic state.
Solution Approach 2:
The patent replaces the conventional direct current-through-MTJ switching mechanism with a spin-orbit torque mechanism. The channel layer converts electrical current into spin current that acts on the magnetic moments, substituting a more energy-efficient mechanism that reduces power consumption while maintaining data retention capability.
3Measurement precision
If conventional MRAM devices are used, then magnetic field sensing is achieved, but sensitivity is limited and temperature susceptibility increases
Solution Approach 1:
The channel layer serves as an intermediary that decouples the read current from direct interaction with the magnetic layers. This allows the MTJ to function as a sensitive magnetic field sensor without being directly affected by write current heating, improving sensitivity while reducing temperature susceptibility.
Solution Approach 2:
Separating the read and write paths allows the MTJ to operate independently for sensing applications. The read current path remains undisturbed by write operations, enhancing measurement precision and sensitivity while the SOT mechanism in the channel layer reduces thermal effects that would otherwise affect temperature stability.
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
This approach results in improved device endurance, read stability, and write speed, reducing side effects like coercivity reduction and heating, while maintaining data retention even without a power source, by leveraging the SOT effect to efficiently switch magnetic moments.
Implementation Method 1
magnetic tunneling junction (MTJ) on a substrate... forming a channel layer in the opening to electrically connect the MTJ and the first metal interconnection
Implementation Method 2
utilizing a spin orbit torque (SOT) approach to switch magnetic moments through an in-plane current, thereby isolating the read/write path
Data Source
Figure 1~2
Figure 3~4
Figure 5~6
AI summary
A method for fabricating a semiconductor device includes the steps of: forming a magnetic tunneling junction (MTJ) on a substrate; forming a first inter-metal dielectric (IMD) layer around the MTJ; forming a first metal interconnection adjacent to the MTJ; forming a stop layer on the first IMD layer; removing the stop layer to form an opening; and forming a channel layer in the opening to electrically connect the MTJ and the first metal interconnection.