Memory Deck Pass Voltage Adjustment for Program Verify Errors
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Solution Overview
Problem
Memory devices with both defective and functional decks experience increased error rates due to threshold voltage shifts and leakage currents, which are not adequately addressed by existing read schemes, leading to inefficiencies and reliability issues.
Innovation Solution
Adaptive adjustment of pass voltages during the program verify phase for wordlines in memory devices with both defective and functional decks, using a memory sub-system controller to determine and apply lower PV pass voltages based on deck configurations and characteristics.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If standard read schemes are used for memory devices with defective decks, then device complexity is reduced, but reliability deteriorates due to increased error rates from threshold voltage shifts and leakage currents
Solution Approach 1:
The patent applies different pass voltages to different wordline groups based on their specific defect characteristics. Functional decks use standard pass voltages while defective decks receive adjusted pass voltages, allowing each local region to be optimized for its operational state without affecting the entire device.
Solution Approach 2:
The system dynamically determines which pass voltage to apply based on real-time detection of defective decks. The controller adjusts pass voltages during program verify operations based on detected deck status, enabling adaptive response to varying device conditions rather than using fixed voltage schemes.
2Reliability
If pass voltage adjustment is applied to compensate for threshold voltage shifts, then reliability improves, but device complexity increases due to additional control logic
Solution Approach 1:
The system performs preliminary detection of defective decks before program verify operations. By identifying which decks are defective in advance, the controller can pre-determine which pass voltages to apply during subsequent operations, avoiding the need for complex real-time adjustments.
Solution Approach 2:
The memory device uses its own operational characteristics (such as threshold voltage measurements during read operations) to automatically identify defective decks and determine appropriate pass voltages. This self-diagnosis capability reduces the need for external intervention or complex control systems.
3Reliability
If adaptive pass voltage adjustment is implemented, then error rates decrease, but operation time increases due to additional voltage determination steps
Solution Approach 1:
Defect detection and pass voltage determination are performed during idle periods or preliminary operations before actual data programming occurs. This advance preparation eliminates the need for time-consuming voltage determination during critical program operations.
Solution Approach 2:
The system uses feedback from read operations and threshold voltage measurements to automatically determine appropriate pass voltages. This feedback mechanism allows rapid adaptation to defective deck conditions without requiring extensive trial-and-error testing or complex sequential operations.
Data Source
AI summary
A system includes a memory device and a processing device, operatively coupled with the memory device, to perform operations including: receiving a request to perform a program operation on a set of cells associated with a wordline in a block of the memory device; determining whether at least one second deck is physically disposed below at least one first deck, wherein the at least one first deck satisfies a criterion pertaining to a functionality of a deck, and the at least one second deck does not satisfy the criterion; and responsive to determining that the at least one second deck is physically disposed below the at least one first deck, performing the program operation on the set of cells using a first pass voltage applied during a program verify phase, wherein the first pass voltage is lower than a default program verify pass voltage.