PCRAM Memory Programming with R-Set and S-Reset Refresh Signals
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing memory technologies face challenges in efficiently programming memory cells, particularly in maintaining the desired logic states without degradation during program operations, especially in non-volatile memory devices like phase change random access memory (PCRAM).
Innovation Solution
A novel programming technique involving r-set and s-reset signals is applied to memory cells, where r-set signals transition cells between set and reset states, and s-reset signals counteract degradation by reversing states, allowing for blind programming without pre-read operations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional programming techniques are used in PCRAM, then programming operations can be performed, but state drift and degradation occur during program operations
Solution Approach 1:
The patent applies preliminary actions by performing refresh operations before the main programming operation. The r-set signal refreshes memory cells that will remain in the set state, and the s-reset signal refreshes memory cells that will remain in the reset state, preventing state drift before programming occurs. This preliminary refreshing ensures stable logic states during subsequent programming operations.
Solution Approach 2:
The patent changes the temporal parameters of signal application by applying refresh signals at specific times before programming. The r-set and s-reset signals are applied during a selection phase before the actual programming phase, changing the timing parameters to prevent degradation while maintaining programming efficiency.
2Measurement precision
If pre-read operations are performed before programming, then accurate state determination is achieved, but operation complexity and time increase
Solution Approach 1:
The patent extracts the refresh function from the traditional pre-read operation. Instead of performing a full read operation to determine cell states, the invention applies targeted refresh signals (r-set and s-reset) that directly refresh cells based on desired final states, eliminating the need for complex pre-read operations while maintaining accuracy.
Solution Approach 2:
The refresh signals serve dual purposes: they both refresh the memory cells to prevent degradation and simultaneously prepare the cells for the desired programming state. This self-service approach eliminates the need for separate pre-read and programming preparation steps, reducing operational complexity.
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 enhances the reliability and efficiency of programming operations by reducing state drift and degradation, ensuring accurate maintenance of logic states in memory cells.
Implementation Method 1
A novel programming technique involving r-set and s-reset signals is applied to memory cells, where r-set signals transition cells between set and reset states
Data Source
Figure 1A
Figure 1B
Figure 2~3
AI summary
The present disclosure includes apparatuses and methods related to program operations in memory. An example apparatus can perform a program operation on an array of memory cells by applying a first program signal to a first portion of the array of memory cells that are to remain in a first state in response to the program operation, wherein the first program signal programs memory cells to a second state and then to the first state.