Variable Resistance Memory Driving Method for Stable Storage
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Solution Overview
Problem
Conventional nonvolatile memory devices with variable resistance elements face challenges in achieving stable storage operations due to variations in resistance values, primarily caused by conflicts between resistance changes induced by oxidation reactions and dielectric breakdowns.
Innovation Solution
A driving method for variable resistance elements involving a low resistance write process and a high resistance write process, where the high resistance write process includes applying a first high resistance writing voltage pulse followed by a second high resistance writing voltage pulse with a lower voltage value, stabilizing the resistance state and reducing variations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a single high resistance writing voltage pulse is applied to change the resistance state to high resistance, then the write operation is simple and fast, but the resistance value variations are large and storage operation stability is poor
Solution Approach 1:
The high resistance write process is segmented into multiple voltage pulse applications: a first high resistance writing voltage pulse to initiate the resistance change, followed by a second high resistance writing voltage pulse to stabilize the resistance value. This segmentation allows the system to achieve both reliable storage operation and controlled resistance variations by breaking down the single complex operation into manageable sequential steps
2Reliability
If a first high resistance writing voltage pulse is applied to change resistance to high state, then the resistance state changes effectively, but the resistance value variations increase due to oxidation reactions and dielectric breakdown conflicts
Solution Approach 1:
The second high resistance writing voltage pulse serves as a preliminary anti-action that counteracts the harmful effects (oxidation reactions and dielectric breakdowns) caused by the first pulse. By applying this compensating pulse immediately after the first pulse, the system prevents resistance value variations before they can significantly degrade the resistance state stability, thus achieving both effective resistance change and high precision
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 method stabilizes the resistance value of the variable resistance layer, ensuring reliable and stable storage operations by effectively managing the resistance changes and reducing variations.
Implementation Method 1
conflicts between resistance changes induced by oxidation reactions and dielectric breakdowns
Implementation Method 2
conflicts between resistance changes induced by oxidation reactions and dielectric breakdowns
Data Source
AI summary
A driving method for driving a variable resistance element and a nonvolatile memory device, which achieves stable storage operation. In a low resistance write process, a low resistance writing voltage pulse having the negative polarity is applied once to a variable resistance layer included in a variable resistance element while in a high resistance write process, a high resistance writing voltage pulse having the positive polarity is applied more than twice to the same variable resistance layer. Here, when a voltage value of one of the high resistance writing voltage pulses is VH1 and a voltage value of the other high resistance writing voltage pulse applied subsequently is VH2, VH1>VH2 is satisfied.