Multilayer MRAM Contact Structure for Thermal Insulation
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Solution Overview
Problem
Thermally assisted MRAM devices require high power to heat the magnetic tunnel junction to a write temperature due to high thermal conductivity with surrounding structures, leading to inefficient energy usage.
Innovation Solution
Incorporating multilayer thermally resistive contact structures with multiple layers of metals that inhibit thermal conductivity while allowing electrical conduction, effectively trapping heat within the magnetic tunnel junction and reducing the power required to reach the write temperature.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If conventional single-layer contact structures are used, then electrical conductivity is achieved, but thermal conductivity is high causing excessive heat loss
Solution Approach 1:
The contact structure is divided into multiple layers (first contact layer, second contact layer, third contact layer) with different materials and thermal conductivities. Each layer segments the thermal conduction path, creating interfacial thermal resistance that reduces heat loss while maintaining electrical conductivity through the stacked configuration.
Solution Approach 2:
The contact structure uses composite materials with different thermal and electrical properties arranged in layers. The first contact layer has high thermal conductivity for heat dissipation in certain directions, while the second and third layers have low thermal conductivity to block heat loss, creating a composite structure that optimizes both thermal and electrical performance.
2Temperature
If high power is applied to heat the magnetic tunnel junction, then write temperature is reached, but energy efficiency deteriorates
Solution Approach 1:
The patent converts the harmful effect of heat loss into a beneficial thermal insulation effect by using low thermal conductivity materials in the second and third contact layers. This insulation traps heat within the magnetic tunnel junction, converting what would be wasted heat into useful thermal energy that maintains the write temperature, thereby improving energy efficiency.
Solution Approach 2:
The patent changes the thermal conductivity parameter of the contact structures by selecting materials with specific thermal properties. The second contact layer uses materials with low thermal conductivity (e.g., tungsten, molybdenum) to reduce heat loss, while the first contact layer uses materials with high thermal conductivity (e.g., copper, aluminum) for optimal electrical contact, thereby optimizing the energy required to reach write temperature.
3Loss of energy
If multilayer contact structures with low thermal conductivity are used, then heat loss is reduced, but electrical conductivity may be compromised
Solution Approach 1:
Different layers of the contact structure have different local qualities optimized for specific functions. The first contact layer has high thermal and electrical conductivity for optimal electrical contact with the magnetic tunnel junction. The second contact layer has low thermal conductivity to block heat loss but maintains sufficient electrical conductivity. The third contact layer has high thermal conductivity for heat dissipation away from the junction. This local optimization ensures both thermal management and electrical 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
This solution significantly reduces the power needed to heat the MRAM device to the write temperature, enhancing energy efficiency by minimizing heat loss through the use of interfacial thermal resistance and maintaining efficient electrical conductivity.
Implementation Method 1
The multiple layers of metals are structured to inhibit thermal conductivity between the magnetic tunnel junction and surrounding structures
Implementation Method 2
the multiple layers of metals are structured to electrically conduct electrical current
Implementation Method 3
Thermally assisted magnetoresistive random access memory devices require heating of the magnetic tunnel junction to a write temperature
Data Source
AI summary
A mechanism is provided for a thermally assisted magnetoresistive random access memory device (TAS-MRAM). The device includes a magnetic tunnel junction configured to store data, a first multilayer contact structure positioned on one end of the magnetic tunnel junction, and a second multilayer contact structure positioned on an opposite end of the magnetic tunnel junction. The first multilayer contact structure and the second multilayer contact structure each include multiple layers of metals. The multiple layers of metals are structured to inhibit thermal conductivity between the magnetic tunnel junction and surrounding structures, and the multiple layers of metals are structured to electrically conduct electrical current.