Magnetic Tunnel Junction Sidewall Dielectric Formation
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Solution Overview
Problem
Magnetic tunnel junction structures in MRAM devices often experience electrical shorts due to conductive etch products attaching to the sidewalls during the etching process, which affects the resistance characteristics and reliability of the devices.
Innovation Solution
A method involving multiple etch and oxidation processes using inert gases and radical oxidation to form a sidewall dielectric layer, preventing the attachment of conductive etch products and reducing electrical shorts, thereby improving the resistance characteristics of the magnetic tunnel junction structure.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If physical etching is used to form magnetic tunnel junction pattern, then the magnetic tunnel junction pattern can be formed, but conductive etch products attach to sidewalls causing electrical shorts
Solution Approach 1:
A protective layer is formed on the sidewalls of the magnetic tunnel junction pattern before the etching process. This preliminary protective coating prevents etch products from attaching to the sidewalls, thereby avoiding electrical shorts while maintaining the integrity of the magnetic tunnel junction pattern during fabrication
Solution Approach 2:
The conductive etch products that would normally cause electrical shorts are converted into a beneficial protective coating by applying a protective layer that transforms the harmful etch residue into a non-conductive or less harmful substance on the sidewalls, preventing short circuits
2Reliability
If multiple etch and oxidation processes are performed, then sidewall dielectric layer is formed preventing electrical shorts, but the fabrication process complexity increases
Solution Approach 1:
The protective layer formation is merged with the existing fabrication process flow by integrating it into the standard etch and oxidation sequence. The protective layer is applied during a specific stage of the process, combining multiple functions (protection, dielectric layer formation) into a unified process step rather than adding completely separate operations
Solution Approach 2:
The etch products themselves serve as the material for the protective layer when combined with the oxidation process. The oxidized etch residue naturally forms a dielectric protective coating on the sidewalls, eliminating the need for separate protective material deposition and reducing the number of additional process steps required
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 method effectively prevents electrical shorts and enhances the resistance distribution characteristics of the magnetic tunnel junction structure, simplifying the fabrication process and reducing the need for additional capping layers, thus improving the reliability and performance of MRAM devices.
Implementation Method 1
a first oxidation process to oxidize the first etch product attached on an etched side of the magnetic tunnel junction layer
Data Source
AI summary
A method of fabricating a magnetic tunnel junction structure includes forming a magnetic tunnel junction layer on a substrate. A mask pattern is formed on a region of the second magnetic layer. A magnetic tunnel junction layer pattern and a sidewall dielectric layer pattern on at least one sidewall of the magnetic tunnel junction layer pattern are formed by performing at least one etch process and at least one oxidation process multiple times. The at least one etch process may include a first etch process to etch a portion of the magnetic tunnel junction layer using an inert gas and the mask pattern to form a first etch product. The at least one oxidation process may include a first oxidation process to oxidize the first etch product attached on an etched side of the magnetic tunnel junction layer.