MRAM Magnetoresistive Element Direct Drain Integration
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Solution Overview
Problem
Magnetic random access memory (MRAM) using tunneling magneto resistive (TMR) elements faces challenges in ensuring sufficient current to reverse the magnetization direction due to parasitic resistances associated with contact plugs and electrodes, which hinders effective magnetization reversal in magnetoresistive elements.
Innovation Solution
The MRAM design eliminates contact plugs by directly forming the magnetoresistive element on the drain diffusion layer, reducing parasitic resistances and ensuring adequate current flow by using a semiconductor substrate with a selective transistor and a magnetoresistive element comprising a magnetic storage layer, nonmagnetic layer, and magnetic reference layer, thereby enhancing current delivery to the magnetoresistive element.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If contact plugs are used to connect the drain to the magnetoresistive element, then the magnetic random access memory can be manufactured with conventional processes, but parasitic resistances increase and current delivery to the magnetoresistive element becomes insufficient
Solution Approach 1:
The patent extracts and eliminates the contact plug from the structure by directly forming the magnetoresistive element on the drain diffusion layer. This removal of the intermediate contact plug component eliminates the parasitic resistances associated with it, thereby improving current delivery to the magnetoresistive element while maintaining manufacturability through direct formation processes.
2Stability of the object's composition
If contact plugs are used to connect the magnetoresistive element, then structural connection is achieved, but magnetization reversal becomes difficult due to insufficient current
Solution Approach 1:
The contact plug is extracted from the structure, eliminating the parasitic resistances that hindered sufficient current flow. This enables adequate current to reach the magnetoresistive element for reliable magnetization reversal while maintaining structural connection through direct formation on the drain diffusion layer.
Solution Approach 2:
The magnetoresistive element is merged directly with the drain diffusion layer by forming it in direct contact. This integration eliminates the need for separate contact plugs and their associated parasitic resistances, enabling sufficient current flow for magnetization reversal while maintaining stable structural connection.
3Device complexity
If conventional contact plug structure is used, then manufacturing process is simplified, but parasitic resistances such as contact resistance and plug resistance increase
Solution Approach 1:
The contact plug is extracted from the device structure, eliminating the sources of parasitic resistance including contact resistance between drain and contact plug, contact plug resistance itself, and contact resistance between contact plug and electrode. This reduces energy loss while the magnetoresistive element is directly formed on the drain diffusion layer.
Solution Approach 2:
The electrode structure is merged directly with the drain diffusion layer by forming the magnetoresistive element in direct contact. This integration eliminates intermediate contact structures and their associated parasitic resistances, reducing energy loss without significantly increasing device complexity.
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 ensures sufficient current to reverse the magnetization direction, improving the performance and efficiency of the MRAM by minimizing parasitic resistances and maintaining a highly flat surface for the magnetoresistive element, thus enhancing the magnetization reversal process.
Implementation Method 1
In a recently discussed spin injection writing method, the direction of magnetization is reversed by injecting a current into a magnetoresistive element
Implementation Method 2
a magnetic random access memory (MRAM) using tunneling magneto resistive (TMR) have been developed. The MRAM is configured with a magnetoresistive element including a magnetic tunnel junction (MTJ); therefore, a large magnetoresistance ratio is obtained
Data Source
AI summary
According to one embodiment, there is disclosed a magnetic random access memory comprising: a semiconductor substrate; a selective transistor formed at the surface region of the semiconductor substrate and having a gate electrode, a gate insulating film, a source and a drain; and a magnetoresistive element formed on the drain including a magnetic storage layer in which a magnetization direction is variable, a magnetic reference layer in which a magnetization direction is fixed, and a nonmagnetic layer sandwiched between the magnetic storage layer and the magnetic reference layer.