Semiconductor Memory Device Programming Voltage Control
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Solution Overview
Problem
Semiconductor memory devices face challenges in maintaining data reliability due to variations in threshold voltages of memory cells during programming operations, leading to inconsistent programming results.
Innovation Solution
The semiconductor memory device employs a method where a program permission voltage and a program inhibition voltage are sequentially applied to bit lines coupled to selected memory cells, allowing for precise control of threshold voltage changes during programming, ensuring stable data storage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a program voltage is applied to selected memory cells during programming, then data can be stored in the memory cells, but threshold voltage variations cause inconsistent programming results and reduced data reliability
Solution Approach 1:
The programming operation is divided into multiple sub-operations by sequentially applying program permission voltages and program inhibition voltages to different bit lines. This segmentation allows precise control over which memory cells are programmed and to what threshold voltage level, thereby improving programming consistency despite threshold voltage variations.
Solution Approach 2:
Different bit lines receive different voltages (program permission or program inhibition) during the programming operation. This local differentiation enables selective programming of specific memory cells based on their required threshold voltage changes, ensuring consistent programming results across all selected memory cells.
2Manufacturing precision
If sequential application of program permission voltage and program inhibition voltage is used, then programming consistency is improved, but the programming operation becomes more complex
Solution Approach 1:
The read and write circuit is designed to perform multiple functions: it can apply both program permission voltages and program inhibition voltages to different bit lines during the same programming operation. This multi-functionality enables the sequential voltage application method without requiring additional dedicated circuits, thereby managing complexity while achieving programming consistency.
Solution Approach 2:
The programming operation uses dynamic voltage assignment where bit lines are selectively switched between program permission and program inhibition states during the programming process. This dynamic control allows the system to adapt to different programming requirements and achieve consistent results through time-varying voltage patterns.
Data Source
AI summary
The present technique relates to an electronic device, and more particularly, to a semiconductor memory device and an operating method thereof. A semiconductor memory device having improved reliability includes an address decoder applying a program voltage to a selected word line coupled to selected memory cells, among the plurality of memory cells, and a read and write circuit applying a program permission voltage or a program inhibition voltage to bit lines coupled to the selected memory cells, and a control logic controlling the read and write circuit to sequentially apply the program permission voltage and the program inhibition voltage to the bit lines coupled to the selected memory cells when the program voltage is applied.