Magnetic Memory Element Nitrogen Gradient Insulating Film
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Solution Overview
Problem
Magnetic memory elements with nitrogen mixed into CoFeB or MgO layers face degraded coercive properties and leak currents due to interface issues, necessitating improvements in coercivity and current leakage.
Innovation Solution
A magnetic memory element with a columnar stack structure including a reference layer, a barrier layer, and a recording layer, where an insulating film with controlled nitrogen concentration is applied to cover the stack, specifically with nitrogen concentrations of 4×10^29 atoms/m^2 or less at 13 nm and 7×10^30 atoms/m^2 or more at 2 nm from the outer edge, to enhance coercive properties and reduce leak currents.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If nitrogen is mixed into CoFeB or MgO layers, then the magnetic memory element can be formed, but coercive properties are degraded
Solution Approach 1:
The patent applies local quality by creating a nitrogen concentration gradient within the insulating film. The nitrogen concentration is controlled to be higher near the outer surface (7×10^30 atoms/m^2 or more at 2 nm from outer circumferential end) and lower deeper inside (4×10^29 atoms/m^2 or less at 13 nm from outer circumferential end). This localized variation in nitrogen concentration allows the film to simultaneously provide leak current suppression at the interface and maintain coercive properties in the interior regions.
2Ease of manufacture
If nitrogen is mixed into CoFeB or MgO layers, then the magnetic memory element can be formed, but leak current occurs at the interface
Solution Approach 1:
The patent applies local quality by creating a nitrogen concentration gradient within the insulating film. The nitrogen concentration is controlled to be higher near the outer surface (7×10^30 atoms/m^2 or more at 2 nm from outer circumferential end) and lower deeper inside (4×10^29 atoms/m^2 or less at 13 nm from outer circumferential end). This localized variation in nitrogen concentration allows the film to simultaneously provide leak current suppression at the interface and maintain coercive properties in the interior regions.
3Ease of manufacture
If uniform nitrogen concentration is applied in the insulating film, then manufacturing is simplified, but both coercive properties and leak current suppression cannot be optimized simultaneously
Solution Approach 1:
The patent applies local quality by creating a nitrogen concentration gradient within the insulating film. The nitrogen concentration is controlled to be higher near the outer surface (7×10^30 atoms/m^2 or more at 2 nm from outer circumferential end) and lower deeper inside (4×10^29 atoms/m^2 or less at 13 nm from outer circumferential end). This localized variation in nitrogen concentration allows the film to simultaneously provide leak current suppression at the interface and maintain coercive properties in the interior regions.
Solution Approach 2:
The patent applies preliminary action by pre-configuring the nitrogen concentration profile during the insulating film formation process. The film is formed with a predetermined nitrogen concentration distribution that anticipates the dual requirements of leak current suppression and coercive property maintenance, eliminating the need for subsequent complex processing steps to achieve the desired performance.
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 controlled nitrogen concentration improves coercive properties and reduces leak currents, thereby enhancing the overall performance of the magnetic memory element.
Implementation Method 1
an insulating film which contains nitrogen and is provided to cover a lateral surface of the columnar stack, in which in one or both of the recording layer and the barrier layer, a nitrogen concentration is 4×10^29 atoms/m^2 or less in a position of 13 nm inside from an outer circumferential end of the columnar stack
Implementation Method 2
In the recording layer, it is possible to reverse a magnetization direction by using spin transfer torque (STT) or the like
Implementation Method 3
A magnetic random access memory (MRAM) using a magnetoresistive effect element as a storage element has been developed
Data Source
AI summary
Provided are a magnetic memory element in which an improvement in properties, such as an improvement in coercive properties or a reduction in a leak current, can be attained, a method for producing the same, and a magnetic memory. The magnetic memory element, includes: a columnar stack ST in which a reference layer FX having a fixed magnetization direction, a barrier layer TL including a non-magnetic body, and a recording layer FR having a reversible magnetization direction are stacked in this order; and an insulating film which contains nitrogen and is provided to cover a lateral surface of the columnar stack, in which in one or both of the recording layer and the barrier layer, a nitrogen concentration is 7×1030 atoms/m2 or more in a position of 2 nm inside from an outer circumferential end of the columnar stack.