MTJ Layer Structure for Compact, Low-Power MRAM Sensing
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Solution Overview
Problem
Existing magnetoresistive random access memory (MRAM) devices face issues such as high chip area, high cost, high power consumption, limited sensitivity, and susceptibility to temperature variations.
Innovation Solution
A method for fabricating a semiconductor device involving the formation of a magnetic tunneling junction (MTJ) with specific layer structures, including a pinned layer, barrier layer, and free layer, and a spacer, optimized through processes like ion beam etching and chemical mechanical polishing to enhance device performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If conventional magnetic field sensor technologies (AMR, GMR, MTJ sensors) are used, then magnetic field sensing function is achieved, but chip area is large and cost is high
Solution Approach 1:
The patent combines multiple sensor functions (magnetic field sensing, temperature sensing, and pressure sensing) into a single integrated device structure. The sensing device includes a pinned layer, free layer, and barrier layer configuration that enables simultaneous detection of magnetic field, temperature, and pressure, thereby reducing overall chip area compared to using separate AMR, GMR, or MTJ sensors for each function.
Solution Approach 2:
The sensing device achieves multi-functionality by utilizing the magnetoresistive effect in a way that responds to multiple physical quantities. The resistance change in the magnetic tunneling junction structure can be influenced by magnetic field, temperature, and pressure, allowing a single device to perform multiple sensing functions that would traditionally require separate dedicated sensors.
2Measurement precision
If conventional magnetic field sensor technologies are used, then magnetic field sensing function is achieved, but power consumption is high
Solution Approach 1:
The patent optimizes the sensing device parameters including the thickness and material composition of the barrier layer, pinned layer, and free layer to reduce the current required for achieving sufficient resistance change. By carefully controlling the magnetoresistive effect parameters and the structural dimensions, the device achieves high sensitivity with lower power consumption compared to conventional AMR or GMR sensors.
3Measurement precision
If conventional magnetic field sensor technologies are used, then magnetic field sensing function is achieved, but sensitivity is limited and temperature sensitivity is high
Solution Approach 1:
The patent employs different material compositions and structural configurations in different layers of the sensing device. The pinned layer, barrier layer, and free layer are each optimized with specific materials and thicknesses to achieve desired magnetic and electrical properties. This local optimization allows the device to maintain high sensitivity to magnetic field while reducing unwanted temperature sensitivity through careful material selection and structural design.
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 reduces chip area, lowers power consumption, and improves sensitivity while minimizing temperature sensitivity, resulting in an improved MRAM device.
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. The physical definition of such effect is defined as a variation in resistance obtained by dividing a difference in resistance under no magnetic interference by the original resistance.
Implementation Method 2
optimized through processes like ion beam etching and chemical mechanical polishing to enhance device performance
Data Source
AI summary
A method for fabricating semiconductor device includes the steps of: forming a first inter-metal dielectric (IMD) layer on a substrate; forming a metal interconnection in the first IMD layer; forming a bottom electrode layer and a pinned layer on the first IMD layer; forming a sacrificial layer on the pinned layer; patterning the sacrificial layer, the pinned layer, and the bottom electrode layer to form a first magnetic tunneling junction (MTJ); forming a second IMD layer around the first MTJ; removing the sacrificial layer to form a recess; forming a barrier layer and a free layer in the recess; forming a top electrode layer on the free layer; and patterning the top electrode layer and the free layer to form a second MTJ.