3D Memory Read Control for Hot Carrier Suppression
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Solution Overview
Problem
As integration of memory devices increases, the distance between strings decreases, leading to electrical defects and hot carrier injection due to channel boosting, which reduces memory reliability.
Innovation Solution
A memory device with a three-dimensional structure that includes a control logic to perform a first read operation on a first logical page, adjust channel initialization time based on the page, and perform a channel initialization operation during the read operation to prevent hot carrier injection.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If the distance between strings is decreased to increase integration degree, then storage capacity is improved, but electrical defects and hot carrier injection occur reducing reliability
Solution Approach 1:
The patent applies preliminary action by performing channel initialization operations before read operations to prevent hot carrier injection. The control logic adjusts the channel initialization time based on the accumulated number of read operations, ensuring that the channel is properly initialized before each read operation to prevent electrical defects and maintain reliability as strings are closely spaced for high integration
2Reliability
If channel initialization time is increased to prevent hot carrier injection, then memory reliability is improved, but read operation speed is reduced
Solution Approach 1:
The patent applies dynamics by making the channel initialization time adjustable rather than fixed. The control logic dynamically adjusts the channel initialization time based on the accumulated number of read operations on the selected page. When the accumulated read operations exceed a reference value, the channel initialization time is increased to prevent hot carrier injection; otherwise, it uses a shorter initialization time to maintain fast read operations
Solution Approach 2:
The patent applies parameter changes by modifying the channel initialization time parameter based on operational conditions. The control logic changes the initialization time parameter dynamically: using a first (shorter) initialization time when accumulated read operations are below the reference value, and a second (longer) initialization time when they exceed the reference value, thus optimizing both speed and reliability
3Reliability
If accumulated read operations increase on a page, then channel boosting effect accumulates causing hot carrier injection, but extending channel initialization time for all operations reduces overall read efficiency
Solution Approach 1:
The patent applies local quality by applying different channel initialization times to different operational conditions on the same page. Instead of uniformly increasing initialization time for all read operations, the control logic selectively increases the initialization time only when the accumulated number of read operations on the selected page exceeds the reference value, thereby locally addressing the hot carrier injection problem only where and when it occurs
Solution Approach 2:
The patent applies feedback by having the control logic monitor the accumulated number of read operations on the selected page and adjust the channel initialization time accordingly. The system continuously tracks the read operation count and uses this feedback to dynamically modify the initialization time, increasing it only when the accumulated operations exceed the reference value, thus preventing hot carrier injection while maintaining overall read efficiency
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
The solution enhances memory reliability by preventing hot carrier injection through controlled channel initialization, improving the read operation efficiency and reducing electrical defects.
Implementation Method 1
channel boosting in unselected strings can cause hot carrier injection due to a voltage difference between the selected word line and unselected strings
Implementation Method 2
channel boosting in unselected strings can cause hot carrier injection due to a voltage difference between the selected word line and unselected strings
Data Source
AI summary
The present technology includes a memory device and a method of operating the same. The memory device includes a memory block including pages configured of a plurality of memory cells, a peripheral circuit configured to perform a read operation on a selected page among the pages, and a control logic configured to control the peripheral circuit to perform a first read operation on a first logical page and then perform a second read operation on a second logical page, among the first and second logical pages in the selected page, during the read operation. The control logic is configured to control the peripheral circuit to adjust a channel initialization time according to the first logical page after the first read operation is ended, and perform a channel initialization operation during the channel initialization time during the second read operation.