Magnetic Field-Assisted STTRAM Write Mechanism
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Solution Overview
Problem
Spin Transfer Torque Random Access Memory (STTRAM) experiences longer write operations compared to read operations, affecting its performance, and existing techniques to reduce write time often compromise memory persistence or efficiency.
Innovation Solution
The use of a magnetic field-assisted write mechanism in STTRAM memory, where a magnetic field is directed through ferromagnetic layers to facilitate state changes from parallel to anti-parallel orientation, reducing write times by optimizing the magnetic field alignment and current direction during write operations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of time
If the persistence of memory is reduced to reduce write time, then write time is reduced, but memory reliability deteriorates
Solution Approach 1:
A magnetic field is introduced as an intermediary to assist the write operation. The magnetic field works in conjunction with the spin transfer torque current to switch the magnetization state, enabling faster writing without compromising the inherent persistence of the memory cell. The magnetic field acts as a catalyst that accelerates the switching process while the memory cell's natural retention properties remain intact.
2Reliability
If conventional write operations are used in STTRAM, then memory persistence is maintained, but write time increases
Solution Approach 1:
The invention changes the physical parameters of the write operation by introducing a magnetic field component. By adjusting the magnetic field strength and direction, along with the current parameters, the switching process is accelerated. This parameter modification enables the system to achieve both fast write times and maintained memory persistence, resolving the trade-off between speed and reliability.
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 significantly reduces write times for STTRAM memory by efficiently changing the polarization state from parallel to anti-parallel, thereby enhancing the memory's performance and efficiency while maintaining memory persistence.
Implementation Method 1
a magnetic field is directed through ferromagnetic layers to facilitate state changes from parallel to anti-parallel orientation
Implementation Method 2
Spin Transfer Torque Random Access Memory (STTRAM) is a type of magnetoresistive Random Access Memory (MRAM)
Data Source
Figure 1A
Figure 1B
Figure 1C~1F
AI summary
In one embodiment, a magnetoresistance random access memory (MRAM) such as a spin transfer torque (STT) random access memory (RAM), for example, has a subarray of bitcells and an electro-magnet positioned adjacent the subarray. A magnetic field is directed through a ferromagnetic device of bitcells of the first subarray to assist in the changing of states of bitcells of the subarray from a first state to a second state in which the ferromagnetic device of the bitcell is changed from one of parallel and anti-parallel polarization to the other of parallel and anti-parallel polarization. Accordingly, the content of the subarray may be readily preset or erased to one of the parallel or anti-parallel state with assistance from an electro-magnet. During a normal write operation, the bits to the other state are written. Other aspects are described herein.