Resistive Memory Resistance Measurement Using Pulsed Read Signals
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Solution Overview
Problem
Existing methods for measuring the resistance of resistive memory devices are inefficient, requiring at least 0.1 seconds and often more than 1 second to accurately measure resistance after data is written, making it difficult to assess the device's operational characteristics and reliability in real-time.
Innovation Solution
A method and system that apply a data write pulse followed by a resistance read pulse with a controlled delay, measuring the drop voltage and total current to determine the resistance of the resistive memory device, allowing for accurate measurement within several to hundreds of nanoseconds after data writing.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a direct current is applied to the cell to measure resistance, then the resistance can be measured, but the measurement time becomes at least 0.1 second and often more than 1 second
Solution Approach 1:
The patent applies periodic pulse signals (write pulses and read pulses) instead of continuous direct current to measure resistance. The resistance is measured during the read pulse period after a controlled delay following the write pulse, enabling rapid measurement within nanoseconds while maintaining accuracy through the periodic pulsing mechanism.
Solution Approach 2:
The patent applies a write pulse to set the resistance state of the memory cell before measuring the resistance. By controlling the timing relationship between the write pulse and read pulse, the system can measure the resistance state immediately after writing, eliminating the need to wait for stabilization periods that would otherwise extend measurement time to over 1 second.
2Loss of time
If the resistance is measured immediately after writing data, then the measurement time is reduced, but the resistance has not stabilized and measurement accuracy deteriorates
Solution Approach 1:
The patent dynamically controls the timing between write pulse and read pulse, allowing the measurement to be performed at an optimized moment when the resistance has sufficiently stabilized after the write operation. The delay time between pulses is controlled to balance between measurement speed and resistance stabilization, enabling accurate measurement within nanoseconds rather than requiring prolonged waiting periods.
3Loss of time
If a pulse waveform method is used to measure resistance rapidly, then the measurement time is reduced to nanoseconds, but additional measurement parameters and processing complexity are required
Solution Approach 1:
The patent measures the voltage drop during the read pulse and uses this feedback information to calculate the resistance. The resistance is determined by comparing the voltage drop during the read pulse with the known pulse amplitude and the internal resistance of the test device, providing a straightforward calculation that avoids complex measurement systems while achieving nanosecond-scale measurement speed.
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 rapid and accurate resistance measurement of resistive memory devices, improving the assessment of operational characteristics and reliability, and setting optimal read sensing margins and data determination voltages.
Implementation Method 1
A resistive memory device may store data in cells of the resistive memory device using resistance changes. Thus, the cells may store different data by providing different respective resistances.
Implementation Method 2
measuring a drop voltage at the cell responsive to a pulse waveform output when applying the resistance read pulse to the selected cell, measuring a total current through the cell using the drop voltage and an internal resistance of a test device coupled to the cell
Data Source
AI summary
A method of measuring a resistance of a memory cell in a resistive memory device can be provided by applying a data write pulse to a selected cell of the resistive memory device, applying a resistance read pulse to the selected cell after a delay time measured from a time of applying the data write pulse, measuring a drop voltage at the cell responsive to a pulse waveform output when applying the resistance read pulse to the selected cell, measuring a total current through the cell using the drop voltage and an internal resistance of a test device coupled to the cell, and determining a resistance of the resistive memory device using the total current and a voltage of the resistance read pulse.