Protective Layer for MRAM Conductive Plug Oxidation
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Solution Overview
Problem
Magnetic random access memory (MRAM) devices exhibit poor performance due to high contact resistance and reduced tunneling magnetic flux ratio (TMR) caused by oxidation of conductive plugs during the formation of magnetic tunnel junction (MTJ) structures, leading to suboptimal contact performance between MTJ laminated structures and conductive plugs.
Innovation Solution
A protective layer is formed on the conductive plug before forming the aligner trench, which prevents oxidation during the mask layer removal process, allowing the MTJ laminated structure to be in direct contact with the conductive plug, thereby reducing contact resistance and improving contact performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If the mask layer is removed by oxygen-containing gas during aligner trench formation, then the mask layer is effectively removed, but the conductive plug is oxidized forming metal oxide layers that increase contact resistance
Solution Approach 1:
A protective layer is introduced as an intermediary between the oxygen-containing gas and the conductive plug. This protective layer allows the mask removal process to proceed while preventing oxygen from reaching and oxidizing the conductive plug, thus maintaining low contact resistance
Solution Approach 2:
The protective layer creates an inert environment around the conductive plug during the mask removal process. By preventing oxygen exposure in this localized region, the conductive plug remains protected from oxidation while the rest of the structure undergoes the necessary processing
2Device complexity
If the protective layer is not formed, then the process is simpler, but the conductive plug oxidizes and contact performance deteriorates
Solution Approach 1:
The protective layer is formed in advance before the aligner trench formation process. This preliminary action ensures that the conductive plug is protected from oxidation before the oxygen-containing gas is introduced, preventing contact resistance issues before they can occur
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 effectively reduces contact resistance and enhances the tunneling magnetic flux ratio (TMR) of the MTJ laminated structure, thereby improving the overall performance of the MRAM device by ensuring direct contact and minimizing the formation of metal oxide layers.
Implementation Method 1
The protective layer formed in embodiments and implementations of the present disclosure can play a role of protecting the conductive plug during the removal of the mask layer to prevent being oxidized of the conductive plug due to exposure to the oxygen-containing atmosphere
Implementation Method 2
When the polarization directions of the two electromagnetic layers are parallel, the tunneling current flowing through the MTJ structure has a maximum value, and the resistance of the MTJ structure unit is relative low. When the polarization directions of the two magnetic layers are anti-parallel, the tunneling current flowing through the MTJ structure has a minimum value, and the resistance of the MTJ structure unit is relative high
Implementation Method 3
The two electromagnetic layers can maintain two magnetic polarization fields separated by the insulation layer. One of the magnetic polarization fields is a fixed magnetic layer having a fixed polarization direction, and the other magnetic polarization field is a free-rotating magnetic layer having a polarization direction that can change with changes of an external field
Data Source
AI summary
A semiconductor structure and a formation method thereof are disclosed. The formation method includes: providing a base; forming a dielectric layer on the base; forming a conductive via running through the dielectric layer; forming a conductive plug in the conductive via; forming a protective layer on the dielectric layer, wherein the protective layer covers the conductive plug; forming an aligner trench in the protective layer and the dielectric layer, wherein the aligner trench is isolated from the conductive plug; after forming the aligner trench, removing the protective layer to expose a top portion of the conductive plug; and after removing the protective layer, forming a magnetic tunnel junction (MTJ) laminated structure on the conductive plug. The protective layer formed in embodiments and implementations of the present disclosure may play a role of protecting the conductive plug, so as to prevent formation of metal oxide caused by oxidization of the conductive plug, which is then conducive to enabling the MTJ laminated structure and the conductive plug, correspondingly improving contact performance of the MTJ laminated structure and the conductive plug, and further improving performance of a magnetic random access memory (MRAM) device.