Resistive Memory Cell Heavy Forming Voltage Control
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Current resistive memory storage technologies face challenges in determining the reliability of memory cells for high temperature data retention and endurance, particularly after forming and reset operations, which affects their suitability for one-time programmable memory devices.
Innovation Solution
The method involves applying a forming voltage to a resistive memory cell and adjusting it based on the cell current relative to a reference current to ensure the cell operates in a heavy forming mode, enhancing its reliability for one-time programmable applications, and optionally performing a reset operation to enable multiple-time programmable functionality.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a forming voltage is applied to a memory cell to obtain a low resistance state, then a large read current is obtained, but it is unknown whether the filament is strong enough to pass high temperature data retention and endurance tests
Solution Approach 1:
The patent changes the forming voltage parameter by applying a second forming voltage that is higher than the first forming voltage. This parameter change enables the system to transition from a standard forming mode to a heavy forming mode, creating a stronger filament that can pass high temperature data retention and endurance tests. The higher voltage parameter directly addresses the reliability concern by ensuring sufficient filament strength.
2Reliability
If a reset operation is performed on a memory cell to obtain a high resistance state, then a small read current is obtained, but it is unknown whether the filament is strong enough to pass the HTDR and endurance tests
Solution Approach 1:
The patent applies a preliminary heavy forming operation (applying a second forming voltage higher than the first) before the reset operation. This preliminary action creates a robust filament structure that maintains sufficient strength even after the reset operation breaks down part of the filament. The preliminary heavy forming ensures that the remaining filament after reset is still strong enough to pass reliability tests.
3Reliability
If the first forming voltage is increased to create a stronger filament, then high temperature data retention is improved, but the complexity of determining the appropriate voltage increases
Solution Approach 1:
The patent implements a feedback mechanism where the system measures the read current of the memory cell and compares it against a threshold value. Based on this feedback, the system determines whether to apply a second forming voltage. This feedback loop simplifies the voltage determination process by using an automated decision rule: if read current is below the threshold, apply higher forming voltage; otherwise, proceed with standard operations.
Data Source
AI summary
An operating method of a resistive memory storage apparatus includes: applying a forming voltage to a memory cell and obtaining a cell current of the memory cell; and determining whether to adjust the forming voltage and apply the adjusted forming voltage to the memory cell according to a magnitude relationship between the cell current and a reference current. The memory cell to which the forming voltage is applied operates in a heavy forming mode and serves as a one-time programmable memory device.