Spin-Orbit Torque Memory Cell With Oxygen-Ion Polarity Control
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Solution Overview
Problem
Existing semiconductor memory devices face challenges in achieving high integration density and low power consumption while maintaining fast operating speeds and reduced latency.
Innovation Solution
A semiconductor memory device utilizing a spin-orbit torque (SOT) mechanism, featuring a spin-orbit coupling (SOC) channel layer, data storage patterns with a free layer and oxygen reservoir layer, and programmable access transistors, allowing for dynamic spin-orbit torque polarity modulation through oxygen ion migration controlled by gate voltage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional magnetic memory devices are used, then non-volatility and reduced latency are achieved, but integration density and power consumption remain suboptimal
Solution Approach 1:
The patent combines multiple functions into a single memory cell structure by integrating the spin-orbit coupling channel layer, free layer, and oxygen reservoir layer into one unified device architecture. This merging approach increases integration density while maintaining non-volatile memory functionality, as the same structure performs both data storage and spin-orbit torque generation without requiring separate components.
Solution Approach 2:
The spin-orbit coupling channel layer serves multiple functions simultaneously: it acts as both the data storage medium and the source of spin-orbit torque for writing data. This multi-functionality reduces the number of components needed, thereby improving integration density while preserving the non-volatile characteristics of magnetic memory.
2Reliability
If conventional magnetic memory devices are used, then non-volatility is achieved, but power consumption is not sufficiently reduced
Solution Approach 1:
The patent utilizes voltage-controlled oxygen ion migration to dynamically change the magnetic properties of the free layer. By applying a gate voltage, oxygen ions are migrated in or out of the free layer, switching its magnetization state. This parameter change approach enables low-power operation because voltage control requires significantly less energy than traditional current-based magnetic switching, while maintaining non-volatile data storage.
Solution Approach 2:
The patent replaces traditional current-based magnetic field generation with voltage-controlled oxygen ion migration to switch magnetization states. This substitution reduces power consumption because electrical field control through voltage requires far less energy than generating magnetic fields through high currents, while still achieving the same data writing function and maintaining non-volatility.
3Use of energy by moving object
If spin-orbit torque mechanism is used, then power consumption is reduced, but additional current polarity changing circuits are required
Solution Approach 1:
Instead of using separate circuits to change current polarity for writing data, the patent inverts the approach by using voltage polarity applied to the gate electrode to directly control oxygen ion migration direction. By applying positive or negative voltage to the gate, oxygen ions are migrated in or out of the free layer, switching its magnetization state without requiring current polarity changes in the main data line, thus simplifying the circuit architecture.
Solution Approach 2:
The gate electrode serves as an intermediary between the control circuit and the free layer. Instead of directly controlling the free layer with current polarity changes, the gate electrode mediates the control by using voltage to induce oxygen ion migration, which then switches the magnetization state. This intermediary approach eliminates the need for complex current polarity changing circuits while maintaining low power consumption.
4Device complexity
If integration density is increased, then device size is reduced, but manufacturing precision requirements increase
Solution Approach 1:
The patent segments the memory device into distinct functional layers (spin-orbit coupling channel layer, free layer, oxygen reservoir layer) that can be fabricated separately and then stacked. This segmentation allows each layer to be optimized and fabricated independently with standard semiconductor manufacturing processes, reducing the overall manufacturing precision requirements while achieving high integration density through vertical stacking.
Solution Approach 2:
The patent transitions from planar integration to vertical stacking by arranging the spin-orbit coupling channel layer, free layer, and oxygen reservoir layer in the vertical dimension. This dimensional change allows high integration density to be achieved through layer stacking rather than lateral miniaturization, thereby avoiding the exponentially increasing manufacturing precision requirements that come with scaling down in the lateral direction.
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
Enables high integration density and reduced power consumption with improved data storage efficiency and faster operating speeds by selectively programming memory cells using spin-orbit torque, reducing the need for additional current polarity changing circuits.
Implementation Method 1
a spin-orbit coupling (SOC) channel layer in common contact with the first sides of the data storage patterns, the SOC channel layer is configured to provide a spin-orbit torque to the data storage patterns
Implementation Method 2
an oxygen reservoir layer in contact with the free layer... each of the data storage patterns may be configured such that an amount of oxygen in an interface region between the free layer and the SOC channel layer is adjusted by a voltage applied thereto
Data Source
AI summary
A semiconductor memory device may be provided. The semiconductor memory device may include data storage patterns having respective first sides and respective second sides, a spin-orbit coupling (SOC) channel layer in common contact with the first sides of the data storage patterns, the SOC channel layer is configured to provide a spin-orbit torque to the data storage patterns, read access transistors connected between the second sides of respective ones of the data storage patterns and respective data lines, a write access transistor connected between a first end of the SOC channel layer and a source line, and a bit line connected to a second end of the SOC channel layer. Each of the data storage patterns comprises a free layer in contact with the SOC channel layer and an oxygen reservoir layer in contact with the free layer.