Magnetic Memory Shielding TMR Elements from External Fields
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Solution Overview
Problem
Magnetic random access memory (MRAM) faces challenges in minimizing writing errors due to external magnetic fields, particularly in highly integrated devices where internal magnetic fields from adjacent TMR elements interfere, leading to increased power consumption and potential data loss.
Innovation Solution
A magnetic memory design incorporating a ferromagnetic yoke structure with a gap to shield TMR elements from external magnetic fields, featuring a close yoke adjacent to the TMR element and a distant yoke with a thickness of 50 nm or more, which generates an internal magnetic field opposite to external fields, reducing the likelihood of magnetization reversal and writing errors.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If the coercivity of the first magnetic layer is decreased to reduce write current, then power consumption is reduced, but the magnetization can be reversed by mistake by external magnetic fields or magnetic fields generated by adjacent lines, resulting in increased writing errors
Solution Approach 1:
A magnetic shield layer is introduced as an intermediary between the TMR element and external magnetic fields. This shield layer, positioned adjacent to the TMR element, absorbs or redirects external magnetic field lines, preventing them from directly reaching the first magnetic layer. Consequently, the TMR element can use lower coercivity for reduced power consumption while the magnetic shield protects against spurious magnetization reversal from external or adjacent line fields.
2Object-affected harmful factors
If a magnetic shield is used to block external magnetic fields, then writing errors from external fields are reduced, but it cannot prevent interfering magnetic fields generated by adjacent lines within the package
Solution Approach 1:
Instead of using a uniform magnetic shield structure, the invention employs a localized magnetic shield layer positioned specifically adjacent to each TMR element. This local shielding approach creates individual protection zones around each memory cell, effectively blocking external magnetic fields at the source while also containing the magnetic fields generated by adjacent lines, preventing them from interfering with neighboring elements.
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 minimizes writing errors and external magnetic field effects on TMR elements, maintaining low power consumption and data integrity in MRAM, even in harsh environments with integrated storage arrays.
Implementation Method 1
a shield structure for shielding the magnetoresistive element against external magnetic field caused by factors other than the part of the line
Implementation Method 2
a ferromagnetic yoke structure with a gap to shield TMR elements from external magnetic fields
Implementation Method 3
a tunneling magnetoresistive (TMR) element arranged between the bit line and the word line at the intersection of the two lines
Data Source
AI summary
A magnetic memory is less susceptible to external magnetic fields and, thus, to writing errors and other adverse effects caused by external magnetic fields. In the magnetic memory, a magnetoresistive element is arranged adjacent to a part of a conductor line. A shield structure is also arranged to shield the magnetoresistive element against external magnetic fields generated by factors other then the part of the line.