Memory Programming Pulse Control for Low-Temperature NAND Cells
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Solution Overview
Problem
The miniaturization of CMOS memory devices leads to diminished string driver capabilities, resulting in insufficient high program voltage and potential program failure, particularly at lower temperatures, and variations in critical dimensions across memory cell layers cause inconsistent programming.
Innovation Solution
Adaptive adjustment of program voltage pulse width based on temperature and critical dimensions, with longer pulse durations at lower temperatures and earlier verification of programmed states to prevent over-programming.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If the memory device is miniaturized to reduce size, then device dimensions are reduced, but string driver capabilities are diminished resulting in insufficient program voltage
Solution Approach 1:
The patent implements dynamic adjustment of program voltage pulse width based on real-time temperature sensing. The system transitions from static fixed-width pulses to dynamic variable-width pulses that adapt to operating conditions, allowing the string driver to compensate for its diminished capability through temporal modulation rather than spatial scaling
Solution Approach 2:
The patent changes the temporal parameter (pulse width) of the program voltage to compensate for the reduced voltage capability. By varying the duration of voltage application based on temperature conditions, the system achieves effective programming without requiring higher peak voltages, thus working around the power limitation imposed by miniaturization
2Reliability
If program voltage is increased to compensate for diminished driver capabilities, then programming reliability improves, but device wear increases reducing lifespan
Solution Approach 1:
Instead of increasing voltage amplitude which accelerates wear, the patent changes the temporal parameter (pulse width) to achieve reliable programming. This parameter substitution allows the system to maintain programming effectiveness while operating at lower voltage stress levels, thereby extending device lifespan
Solution Approach 2:
The patent employs periodic program/verify cycles with dynamically adjusted pulse widths. This periodic approach with adaptive timing allows thorough programming verification without sustained high-voltage exposure, reducing cumulative wear while maintaining reliability
3Device complexity
If fixed program pulse width is used across all temperatures, then device complexity is reduced, but programming consistency deteriorates at varying temperatures
Solution Approach 1:
The patent implements self-service through integrated temperature sensing and automatic pulse width adjustment. The system monitors its own operating conditions and autonomously adapts programming parameters without external intervention, maintaining programming consistency while adding minimal control complexity through feedback-based regulation
Solution Approach 2:
The patent incorporates temperature feedback into the programming control loop. The sensed temperature information feeds back to adjust the pulse width dynamically, creating a closed-loop system that maintains programming consistency across varying thermal conditions without requiring complex external control mechanisms
Data Source
AI summary
Methods, systems, and apparatus for management of program operations in a memory system are described. An example system includes a memory device and a memory controller. The memory device includes a memory cell array and a peripheral circuit coupled to the memory cell array. The peripheral circuit obtains a first temperature, and in response to determining that the first temperature is at or above a predetermined threshold, apply a first program voltage pulse with a first pulse width to a specified word line coupling memory cells of the memory cell array. The peripheral circuit obtains obtain a second temperature, and in response to determining that the second temperature is below the predetermined threshold, apply a second program voltage pulse with a second pulse width to the specified word line, where the second pulse width is larger than the first pulse width.