SOT Magnetic Tunnel Junction Logic Device
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Solution Overview
Problem
Current semiconductor devices face challenges in achieving high-speed information saving, recognition, and transfer with low energy consumption while maintaining high integration and reducing production costs, particularly in controlling magnetization direction for magnetic memory devices.
Innovation Solution
The semiconductor device employs the spin orbit torque (SOT) effect using a magnetic tunnel junction (MTJ) with a free magnetic layer and a pinned magnetic layer separated by a dielectric layer, where the magnetization direction is changed by applying current exceeding a critical value, and voltage is used to control the critical current, enabling efficient information storage and retrieval.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If spin-polarized current is applied through the magnetic material to control magnetization direction, then magnetization switching is achieved, but high energy consumption occurs
Solution Approach 1:
The patent introduces a heavy metal layer as an intermediary between the current path and the magnetic material. The spin-orbit torque generated in the heavy metal layer mediates the magnetization switching process, eliminating the need for high-current direct passage through the magnetic material and thereby reducing energy consumption while maintaining reliable magnetization control.
Solution Approach 2:
The patent changes the physical parameters of the magnetic memory device by introducing a heavy metal layer with specific spin-orbit coupling properties. This parameter change enables the use of spin-orbit torque instead of spin-transfer torque, allowing magnetization switching at lower current densities and reducing overall energy consumption while maintaining switching reliability.
2Productivity
If more cells are integrated on the electrode, then high integration is achieved, but device complexity increases
Solution Approach 1:
The patent merges multiple cell control functions into a single electrode structure. By applying current to specific regions of the electrode, multiple cells can be selectively addressed and controlled without requiring separate control lines for each cell, thereby achieving high integration density while minimizing the increase in device complexity.
Solution Approach 2:
The electrode serves multiple functions: it acts as both the current path for spin-orbit torque generation and the control line for selective cell addressing. This multi-functionality allows high integration of multiple cells without proportionally increasing the number of control structures, thus improving integration density while keeping device complexity manageable.
3Ease of operation
If different critical current values are set for different cells, then selective magnetization control is achieved, but manufacturing precision requirements increase
Solution Approach 1:
The patent applies local quality by creating spatial variations in the heavy metal layer or magnetic layer properties at different cell locations. This allows each cell to have different critical current values through localized material composition or thickness adjustments, enabling selective control while using standard manufacturing processes that can handle local variations without requiring extreme precision across the entire device.
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 approach results in high-speed information processing with low energy consumption, facilitates high integration, and reduces production costs by allowing for the realization of logic gates like AND, OR, NAND, and NOR, while enabling flexible magnetization control for various applications.
Implementation Method 1
the magnetization direction of the free magnetic layer is changed when the current applied on the surface of the first electrode exceeds critical current value of each cell
Implementation Method 2
It provides information through the magnetoresistance of the device that would be changed according to the relative magnetization direction of the two different magnetic materials
Data Source
AI summary
The present invention relates to a semiconductor device. The semiconductor device based on the spin orbit torque (SOT) effect, according to an example of the present invention, comprises the first electrode; and the first cell and the second cell connected to the first electrode, wherein the first and the second cells are arranged on the first electrode separately; the magnetic tunnel junction (MTJ) having a free magnetic layer and a pinned magnetic layer with a dielectric layer in between them; the magnetization direction of the free magnetic layer is changed when the current applied on the first electrode exceeds critical current value of each cell; and the critical current value of the first cell is different from that of the second cell.