MRAM Top Electrode Liner Structure to Prevent MTJ Shorting
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Solution Overview
Problem
In MRAM devices, electrical shorting can occur between the magnetic tunnel junction (MTJ) stack and the top metal contact due to improper etching of the top metal layer contact hole, which exposes sidewalls of the MTJ stack layers.
Innovation Solution
A dielectric liner layer is formed around the top metal contact hole to electrically isolate the top metal layer from the MTJ stack, preventing shorting by covering the exposed sidewalls and acting as an insulating barrier during the formation of the top metal contact.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If top metal layer contact holes are etched to connect to the top electrode, then electrical connection is achieved, but electrical shorting may occur between the top metal layer and the MTJ stack
Solution Approach 1:
A dielectric liner layer is deposited conformally on the sidewalls of the contact hole to act as an insulating barrier between the top metal layer and the MTJ stack. This intermediary layer prevents direct electrical contact while allowing the top metal layer to maintain electrical connection to the top electrode through the contact hole fill process.
2Object-affected harmful factors
If a dielectric liner layer is conformally deposited to prevent electrical shorting, then electrical isolation is improved, but the contact hole formation process becomes more complex
Solution Approach 1:
The dielectric liner layer is deposited conformally on the sidewalls of the contact hole before the contact hole is fully formed and before the top metal layer is deposited. This preliminary action ensures that the insulating barrier is already in place to prevent electrical shorting between the top metal layer and the MTJ stack, simplifying the overall process by preventing defects rather than requiring additional corrective steps.
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 dielectric liner layer effectively prevents electrical shorting by isolating the top metal contact from the MTJ stack, ensuring reliable operation and preventing potential failures in MRAM devices.
Implementation Method 1
a dielectric liner layer formed in the top metal contact hole... effectively isolates the top metal layer from the MTJ stack, preventing electrical shorts
Data Source
AI summary
A semiconductor device is provided. The semiconductor device includes a memory including a bottom electrode, a magnetic tunnel junction (MTJ) stack on the bottom electrode, and an upper electrode on the MTJ stack. The semiconductor device also includes at least one dielectric layer formed around the memory, wherein a top metal layer contact hole is formed in the at least one dielectric layer, a dielectric liner layer formed in the top metal contact hole, and a top metal layer contact in the top metal layer contact hole.