Adaptive Program Voltage Tuning for Cycling-Aged Memory Cells
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Solution Overview
Problem
Program and erase cycling in non-volatile memory devices leads to performance degradation, which is not adequately addressed by existing smart verify methods that use a fixed initial program voltage.
Innovation Solution
Adaptive adjustment of the initial program voltage based on cycling conditions in smart verify operations to optimize programming efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If smart verify uses a fixed initial program voltage to improve programming speed, then programming efficiency is improved, but performance degradation from cycling is not adequately addressed
Solution Approach 1:
The initial program voltage is changed from a fixed value to a dynamically adjustable parameter that adapts based on cycling conditions. The system monitors the number of program/erase cycles and adjusts the initial program voltage accordingly, allowing the voltage to evolve with the memory device's aging and usage patterns, thus maintaining optimal programming performance while accounting for cycling-induced degradation
Solution Approach 2:
The patent modifies the initial program voltage parameter based on cycling conditions. By changing this electrical parameter adaptively rather than keeping it constant, the system compensates for performance degradation caused by repeated program/erase operations, thereby maintaining both high programming speed and reliable operation over the device's lifetime
2Reliability
If program voltage is increased to compensate for cycling degradation, then reliability is improved, but programming time increases
Solution Approach 1:
The system performs preliminary assessment of cycling conditions before executing the programming operation. By evaluating the number of previous program/erase cycles in advance, the system can pre-determine the appropriate initial program voltage, avoiding the need to use excessively high voltages and thus preventing unnecessary programming time extension while still ensuring reliable programming
Solution Approach 2:
The patent implements a feedback mechanism where the system monitors cycling history and uses this information to adjust the initial program voltage. This closed-loop approach ensures that voltage is increased only to the extent necessary to compensate for actual cycling degradation, rather than using a fixed conservative voltage that would always result in longer programming times
Data Source
AI summary
A memory apparatus includes memory cells connected to word lines. The memory cells are disposed in memory holes and are configured to retain a threshold voltage corresponding to data states. The memory holes are organized in rows grouped in strings which comprise each of a plurality of blocks. A control means is configured to acquire a smart verify programming voltage by programming the memory cells connected to one of the word lines and associated with one of the strings in a smart verify operation including a plurality of smart verify loops beginning with an initial program voltage. The initial program voltage is adjusted based on a cycling condition of the memory cells. The control means is also configured to program at least some of the memory cells connected to the word lines in a program operation using the smart verify programming voltage based on the adjusted initial program voltage.