MTJ Interconnection Structure for Smaller, Temperature-Stable MRAM
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Solution Overview
Problem
Current magnetoresistive random access memory (MRAM) devices face issues such as high chip area, high cost, high power consumption, and sensitivity to temperature variations, limiting their effectiveness in magnetic field sensor applications.
Innovation Solution
A semiconductor device with a magnetic tunneling junction (MTJ) on a substrate, featuring a spacer and liners adjacent to the MTJ, and metal interconnections with protrusions that contact the liners directly, optimized through specific etching and deposition processes to enhance structural alignment and reduce material usage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Area of stationary object
If conventional MRAM device structures are used, then data storage functionality is achieved, but chip area is large and cost is high
Solution Approach 1:
The device structure is segmented into distinct functional regions: MTJ region with vertical stack, first interconnection region with metal traces, and second interconnection region with different metal traces. This segmentation allows optimized material usage and reduced chip area by placing each component only where needed, eliminating redundant structures.
Solution Approach 2:
The patent transitions from planar 2D layouts to 3D vertical stacking in the MTJ region, with multiple layers deposited at different angles (0°, 45°, -45°). This dimensional change reduces the horizontal chip area while maintaining functionality, directly addressing the large chip area problem.
2Use of energy by moving object
If conventional MRAM device structures are used, then data storage functionality is achieved, but power consumption is high
Solution Approach 1:
The patent changes material parameters by using specific compositions: CoFeB (cobalt-iron-boron) for the ferromagnetic layer instead of conventional CoFe, and MgAlO3 (magnesium aluminum oxide) for the tunnel barrier instead of pure MgO. These parameter changes reduce switching current and power consumption while maintaining data storage reliability through enhanced magnetoresistance ratios.
3Measurement precision
If conventional MRAM device structures are used, then basic sensing functionality is achieved, but sensitivity is limited and temperature stability is poor
Solution Approach 1:
The patent employs composite material structures: CoFeB ferromagnetic layer combined with MgAlO3 tunnel barrier, and multi-layered interconnection structures with different metals (Cu, Al, W) and dielectric materials (SiO2, Si3N4). These composite materials provide enhanced temperature stability and sensitivity by compensating for thermal effects and improving magnetoresistance characteristics.
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 reduces chip area, lowers costs, and improves sensitivity and temperature stability, addressing the shortcomings of existing MRAM devices.
Implementation Method 1
Magnetoresistance (MR) effect has been known as a kind of effect caused by altering the resistance of a material through variation of outside magnetic field
Data Source
AI summary
A semiconductor device includes a magnetic tunneling junction (MTJ) on a substrate, a spacer adjacent to the MTJ, a liner adjacent to the spacer, and a first metal interconnection on the MTJ. Preferably, the first metal interconnection includes protrusions adjacent to two sides of the MTJ and a bottom surface of the protrusions contact the liner directly.