Two-Layer Electrode Structure for MRAM Contact Area
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
In magnetoresistive random access memory (MRAM) devices using magnetic tunnel junction (MTJ) elements, securing sufficient contact areas between lower electrodes and MTJ elements, as well as between lower electrodes and transistors, is challenging due to the need for a balance between maintaining contact and avoiding disconnection.
Innovation Solution
The implementation of a two-layer electrode structure where the first lower electrodes are positioned to deviate from the second lower electrodes, ensuring a large overlapping area with the landing-plug contact while maintaining contact with the transistor drain, and using materials like TiN and Ta for low resistance and improved MTJ element characteristics.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Area of stationary object
If a single-layer lower electrode structure is used, then the device structure is simple, but the contact area between the lower electrode and MTJ element is insufficient
Solution Approach 1:
The lower electrode is divided into two separate layers: a first lower electrode and a second lower electrode. The first lower electrode provides a large contact area with the transistor drain, while the second lower electrode provides a large contact area with the MTJ element. This segmentation allows each layer to be optimized for its specific contact requirement, thereby increasing the overall contact area without requiring a single complex electrode structure.
Solution Approach 2:
The patent transitions from a single-layer (one-dimensional) electrode structure to a two-layer (two-dimensional) electrode structure. By adding the vertical dimension with the first and second lower electrodes stacked at different positions, the patent achieves sufficient contact area with both the transistor drain and MTJ element simultaneously, resolving the contradiction between contact area and structural simplicity.
2Area of stationary object
If the first lower electrode and second lower electrode are positioned at the same location, then the alignment is simple, but the contact area with both transistor and MTJ element is insufficient
Solution Approach 1:
The first lower electrode and second lower electrode are positioned at different locations: the first lower electrode is positioned to overlap with the transistor drain, while the second lower electrode is positioned to overlap with the MTJ element. This local differentiation allows each electrode layer to serve its specific function with adequate contact area, while the overall structure maintains manufacturing feasibility through defined positioning relationships.
3Reliability
If the contact area between lower electrode and MTJ element is increased, then the connection resistance is reduced, but the risk of disconnection between electrode and transistor increases
Solution Approach 1:
By segmenting the lower electrode into two separate layers, the patent eliminates the trade-off between contact area and disconnection risk. The first lower electrode maintains reliable connection with the transistor drain, while the second lower electrode provides sufficient contact area with the MTJ element. This segmentation allows both connection stability and adequate contact area to be achieved simultaneously without compromising either interface.
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
This configuration increases the contact area between electrodes, reducing connection resistance and improving element characteristics by ensuring secure and efficient contact between MTJ elements and transistors, thereby enhancing the performance of magnetoresistive memory devices.
Implementation Method 1
magnetoresistive effect elements on the respective second electrodes
Data Source
AI summary
According to one embodiment, a magnetoresistive memory device includes first electrodes located in an interlayer insulating film, second electrodes located on the respective first electrodes within the interlayer insulating film, magnetoresistive effect elements on the respective second electrodes, and third electrodes on the respective magnetoresistive effect elements. The first electrodes and the second electrodes are displaced from each other.