MRAM V-Shape Passivation Layer Prevents Over-Etching
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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 method for fabricating MRAM devices involves forming a first magnetic tunneling junction (MTJ) on a substrate, followed by a top electrode and a passivation layer with a V-shape profile, where the valley point of the V-shape is higher than the top surface of the electrode, to optimize device performance and prevent over-etching during subsequent processing steps.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If conventional planar passivation layer is used, then fabrication process is simple, but over-etching occurs during subsequent processing steps
Solution Approach 1:
The passivation layer is formed with a curved profile (convex upward or inclined) instead of a planar surface. This curvature is achieved through selective etching of the passivation layer to create different heights at different locations, which prevents over-etching in subsequent processing steps while maintaining fabrication feasibility
2Reliability
If MRAM devices are designed with larger area, then device performance is improved, but chip area increases
Solution Approach 1:
The patent utilizes vertical dimension by creating passivation layer with varying heights (convex or inclined profiles) to achieve better device performance without increasing the horizontal chip area. The third dimension (height variation) provides the solution to the area-performance tradeoff
3Ease of manufacture
If conventional processing is used, then fabrication cost is low, but temperature sensitivity issues occur
Solution Approach 1:
The patent modifies the passivation layer parameters (profile shape, height, inclination angle) to reduce temperature sensitivity of the MRAM devices. By changing the geometric parameters of the passivation layer rather than the material composition, the solution maintains cost-effectiveness while addressing temperature sensitivity issues
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 V-shape passivation layer design enhances the fabrication process by reducing the risk of over-etching and improving the performance of MRAM devices, addressing the limitations of existing MRAM technologies in terms of chip area, cost, and temperature sensitivity.
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 magnetic random access memory (MRAM) device includes a first magnetic tunneling junction (MTJ) on a substrate, a first top electrode on the first MTJ, and a passivation layer around the first MTJ. Preferably, the passivation layer includes a V-shape and a valley point of the V-shape is higher than a top surface of the first top electrode.