Non-Volatile Memory Programming Pulse Width Adjustment
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Solution Overview
Problem
Non-volatile memory chips face inefficiencies due to charge pump recovery times, leading to wide threshold voltage distributions and slower programming, as the effective voltage seen by memory cells is lower than intended, especially at higher voltages, and current methods either ensure sufficient recovery time at the cost of slower programming or exacerbate the issue with shorter pulse durations.
Innovation Solution
Varying the pulse widths and magnitudes of programming signals based on simulation and physical testing data to compensate for chip non-idealities, allowing for optimized pulse parameters that ensure effective voltage delivery and improved programming performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the charge pump is given sufficient recovery time between programming pulses, then the effective voltage delivery to memory cells is improved, but the programming speed deteriorates
Solution Approach 1:
The patent applies dynamics by making the pulse width a variable parameter that changes based on the pulse magnitude. Instead of using fixed pulse widths, the system dynamically adjusts pulse duration to match the charge pump's recovery characteristics at different voltage levels, optimizing both voltage delivery and programming speed
Solution Approach 2:
The patent changes physical parameters by varying pulse width as a function of pulse magnitude. The simulation data is used to establish relationships between voltage magnitude and optimal pulse duration, allowing the system to adapt parameters in real-time based on operating conditions
2Productivity
If shorter pulse durations are used to increase programming speed, then productivity is improved, but the charge pump cannot recover sufficiently leading to worse voltage delivery and wider threshold voltage distributions
Solution Approach 1:
The system dynamically adjusts pulse width based on pulse magnitude using pre-characterized relationships from simulation. This allows the pulse duration to be optimized for each voltage level, ensuring sufficient charge pump recovery even at higher voltages while maintaining fast programming speeds
Solution Approach 2:
The patent performs preliminary simulation and characterization to establish the relationship between pulse magnitude and optimal pulse width before actual programming operations. This pre-computed data is stored and used to guide real-time pulse generation, eliminating the need for complex real-time calculations while ensuring optimal parameters are always used
Data Source
AI summary
To program a set of non-volatile storage elements, a set of programming pulses are applied to the control gates (or other terminals) of the non-volatile storage elements. The programming pulses have pulse widths that vary as a function of simulated pulse magnitude data. The programming pulses can also have pulse magnitudes that vary based on measurements taken while testing the set of non-volatile storage elements. In one embodiment, the pulse widths are determined after simulation performed prior to fabrication of the non-volatile storage elements. In another embodiment, the pulse magnitudes are calculated after fabrication of the non-volatile storage elements.