Drain-side wordline voltage boosting for memory programming
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Solution Overview
Problem
In memory sub-systems, the lateral electron field during programming operations leads to hot-electron disturb and cell-to-cell interference, causing errors and reliability issues due to the potential difference between source and drain wordlines.
Innovation Solution
Boosting the voltage applied to drain-side wordlines to a higher pass-through voltage level than source-side wordlines, allowing residual electrons to move from the drain to the source, thereby reducing the lateral electric field and minimizing disturb during programming operations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If a programming operation is performed on a target wordline, then data can be programmed into memory cells, but a lateral electron field is generated causing hot-electron disturb and cell-to-cell interference
Solution Approach 1:
The patent applies preliminary action by raising the pass-through voltage of drain-side wordlines before the main programming operation begins. This preliminary voltage adjustment prevents the formation of harmful lateral electron fields during the programming process, thereby eliminating hot-electron disturb and cell-to-cell interference while maintaining programming functionality.
Solution Approach 2:
The patent changes the voltage parameter of drain-side wordlines by applying a higher pass-through voltage compared to source-side wordlines. This parameter change modifies the electric field distribution during programming, suppressing the lateral electron field and its harmful effects while allowing the programming operation to proceed effectively.
2Productivity
If a potential difference is applied between source and drain wordlines, then programming can occur, but residual electrons remain on the drain-side causing disturb to target wordlines
Solution Approach 1:
The patent applies preliminary action by pre-raising the pass-through voltage of drain-side wordlines before the programming operation. This preliminary measure ensures that residual electrons are prevented from accumulating on the drain-side during programming, thereby maintaining both programming productivity and memory device reliability.
Solution Approach 2:
The patent converts the potentially harmful voltage difference between source and drain wordlines into a beneficial configuration by strategically applying higher pass-through voltage to drain-side wordlines. This transformation eliminates the harmful residual electron accumulation while preserving the necessary voltage potential for effective programming operations.
3Ease of operation
If standard pass-through voltage is applied to all wordlines, then the programming operation can proceed, but hot-electron levels and cell-to-cell interference increase
Solution Approach 1:
The patent applies local quality by differentiating the pass-through voltage between drain-side and source-side wordlines. Specifically, drain-side wordlines receive a higher pass-through voltage than source-side wordlines. This localized voltage adjustment suppresses hot-electron generation and cell-to-cell interference in the drain region while maintaining ease of operation for the overall programming process.
Solution Approach 2:
The patent changes the voltage parameter locally by applying a higher pass-through voltage to drain-side wordlines compared to source-side wordlines. This parameter differentiation targets the specific region where hot-electron disturb occurs, reducing harmful effects without complicating the programming operation.
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 reduces the amount of residual electrons on the drain-side, minimizing disturb on target wordlines and enhancing memory device reliability by suppressing hot-electron levels and cell-to-cell interference.
Implementation Method 1
Boosting a voltage applied to drain-side wordlines to a first adjusted pass through voltage level... allowing residual electrons to move from the drain to the source... reducing the lateral electric field
Data Source
AI summary
A request to execute a programming operation to program a set of memory cells associated with a target wordline of a memory device is identified. At a first time during application of a programming voltage to the target wordline, causing a first adjusted pass through voltage to be applied to a first portion of a first set of drain-side wordlines of the memory device. At a second time during application of the programming voltage to the target wordline, causing a second pass through voltage to be applied to a second portion of the first set of drain-side wordlines and to one or more source-side wordlines of the memory device, where the first adjusted pass through voltage is greater than the second pass through voltage.