T-Shaped Top Electrode for MTJ Structural Integrity
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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) structure is fabricated, featuring a T-shaped top electrode and a conductive layer within a recess formed by removing part of the liner, allowing for expanded top electrode area and improved structural integrity during metal interconnective processes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If a conventional MTJ structure is used, then the device structure is simple, but the structural integrity is poor and the MTJ is easily damaged during metal interconnective processes
Solution Approach 1:
The top electrode is extended from a simple planar structure into the liner layer, creating a T-shaped three-dimensional structure. This dimensional extension provides mechanical support and distributes stress, thereby improving the structural integrity of the MTJ device during subsequent processing steps.
Solution Approach 2:
The top electrode is预先 extended into the liner layer during the MTJ fabrication process, before the metal interconnective processes occur. This preliminary structural reinforcement prevents damage during subsequent processing by providing mechanical support in advance.
2Reliability
If the top electrode area is increased to improve stability, then the temperature stability improves, but the chip area increases
Solution Approach 1:
The liner layer acts as a thin film structure that contains the extended top electrode. This allows the electrode area to be increased within the vertical dimension rather than requiring lateral expansion, thereby improving temperature stability without significantly increasing the chip area.
Solution Approach 2:
Instead of increasing the top electrode area in the lateral plane, the electrode is extended vertically into the liner layer. This dimensional transition allows for increased effective electrode area and improved thermal stability without proportionally increasing the chip footprint.
3Strength
If protective layers are added around the MTJ to improve structural integrity, then the MTJ protection improves, but the manufacturing complexity increases
Solution Approach 1:
The top electrode and the protective liner layer are merged into a single integrated T-shaped structure. This eliminates the need for separate protective layers around the MTJ, as the extended electrode itself provides the protection, thereby reducing manufacturing complexity while maintaining integrity.
Solution Approach 2:
The liner layer serves dual functions: it acts as an insulating protective layer and simultaneously contains the extended top electrode structure. This multi-functionality reduces the need for additional protective structures and simplifies the manufacturing process.
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 enhances the structural integrity and reduces the risk of damage to the MTJ during subsequent processing steps, potentially lowering chip area, cost, and power consumption while improving sensitivity and temperature stability.
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 method for fabricating semiconductor device includes the steps of: forming a magnetic tunneling junction (MTJ) on a substrate; forming a liner on the MTJ; removing part of the liner to form a recess exposing the MTJ; and forming a conductive layer in the recess, wherein top surfaces of the conductive layer and the liner are coplanar. Preferably the MTJ further includes: a bottom electrode on the substrate, a fixed layer on the bottom electrode, and a top electrode on the fixed layer, in which the conductive layer and the top electrode are made of same material.