Nonvolatile Memory Channel Boosting Uniform Initial Voltage
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Solution Overview
Problem
In non-volatile memory devices, channel boosting under different initial conditions for inhibit strings makes it difficult to secure an optimal pass voltage window, leading to program disturbances and inefficiencies in programming operations.
Innovation Solution
Applying the same initial channel voltage to all inhibit strings allows for channel boosting under uniform conditions, facilitating the determination of an optimal pass voltage and reducing program time by performing a bit line setup operation together with channel boosting.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If different initial channel voltages are applied to inhibit strings, then the programming operation can be performed, but it becomes difficult to secure an optimal pass voltage window leading to program disturbances
Solution Approach 1:
The patent applies equipotentiality by setting all inhibit strings to the same initial channel voltage (ground voltage) before channel boosting. This uniform starting condition allows all inhibit strings to be boosted simultaneously to the same final voltage level, creating an optimal pass voltage window that prevents program disturbances to non-selected memory cells while enabling effective programming of selected cells.
2Productivity
If channel boosting is performed separately from bit line setup, then each operation can be optimized, but the programming time increases
Solution Approach 1:
The patent merges the bit line setup operation with the channel boosting operation into a single unified process. By combining these two operations, the patent reduces the total programming time and improves productivity while maintaining the effectiveness of both operations through coordinated voltage applications to bit lines and word lines during the same time period.
3Ease of operation
If multiple inhibit strings have different initial voltages, then programming can proceed, but the determination of optimal pass voltage becomes complex
Solution Approach 1:
The patent applies homogeneity by ensuring all inhibit strings have the same initial channel voltage (ground voltage) before channel boosting. This uniform initial condition simplifies the voltage control scheme, making it easier to determine and apply the optimal pass voltage to all inhibit strings simultaneously, thereby reducing the complexity of voltage control while improving ease of operation.
Data Source
AI summary
Non-volatile memory device channel boosting methods in which at least two strings are connected to one bit line, the channel boosting methods including applying an initial channel voltage to channels of strings in a selected memory block, floating inhibit strings each having an un-programmed cell among the strings, and boosting channels of the floated inhibit strings.