VCMA MRAM Cell Layout Without a Selector Element
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Solution Overview
Problem
The configuration of existing VC-MRAM memory cells is complicated due to the inclusion of a selector element, which complicates the magnetization reversal process.
Innovation Solution
A memory cell design that utilizes a magnetoresistive effect element with voltage controlled magnetic anisotropy (VCMA) effect, eliminating the need for a selector element, and employs a driver to apply reversing voltages based on VCMA, along with resistance control circuits and field effect transistors to manage cell voltages and resistances for data writing and reading.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a selector element is included in the memory cell to select the memory cell, then the memory cell can be properly selected for reading and writing operations, but the configuration of the memory cell becomes complicated
Solution Approach 1:
The patent removes the selector element from the memory cell configuration. By extracting this component, the invention simplifies the memory cell structure while maintaining selection capability through alternative means (voltage control of magnetoresistive effect element directly).
Solution Approach 2:
The magnetoresistive effect element is made to serve multiple functions: it acts as both the storage element and the selection element. By applying voltage control directly to the magnetoresistive effect element, the same component performs both data storage and cell selection functions, eliminating the need for separate selector elements.
2Use of energy by moving object
If voltage drive is used for magnetization reversal of the MTJ element, then power consumption is reduced compared with current drive, but the configuration becomes more complex due to additional control circuits
Solution Approach 1:
The patent changes the control parameter from current to voltage for magnetization reversal. By using voltage drive instead of current drive, the system achieves lower power consumption while the magnetoresistive effect element's resistance changes with applied voltage enable direct selection without additional selector elements.
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 design simplifies the memory cell configuration, reduces the reversal probability of non-selected cells, ensures equal cell voltages for resistance transitions, and enables efficient data writing and reading while maintaining a high storage capacity without increasing device size.
Implementation Method 1
the magnetoresistive effect element may have a voltage controlled magnetic anisotropy (VCMA) effect
Implementation Method 2
the VCMA effect may be non-linear. As a result, an effect is provided that a reversal probability of a non-selected cell is reduced while a reversing voltage is applied to a selected cell
Implementation Method 3
the resistance control circuit may include a field effect transistor whose ON-resistance changes on the basis of a gate voltage
Data Source
AI summary
A memory cell capable of reversing magnetization on the basis of voltage drive is achieved without providing a selector element in the memory cell. A storage device includes: a memory cell provided with a magnetoresistive effect element; a word line connected to one end of the magnetoresistive effect element; and a bit line connected to another end of the magnetoresistive effect element. The magnetoresistive effect element may have a voltage controlled magnetic anisotropy (VCMA) effect. A driver configured to apply a reversing voltage for reversing a magnetization direction of the magnetoresistive effect element on the basis of the VCMA effect may be included. The driver may switch a voltage applied to the memory cell such that a reversing voltage is applied to a selected cell while a non-reversing voltage is applied to a non-selected cell, in which the non-reversing voltage does not reverse a magnetization direction of the magnetoresistive effect element.