Semiconductor Memory Read Voltage Universality
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Solution Overview
Problem
Semiconductor memory devices face challenges in maintaining read performance due to the need to change read voltages when reading physical pages programmed through different schemes, leading to deteriorated performance.
Innovation Solution
The semiconductor memory device employs a method where an MLC-program operation or SLC-program operation is performed using logic codes and verify voltages from a TLC-program operation, allowing the same read voltage to be used for physical pages programmed through different schemes, thereby improving read performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If different read voltages are used for physical pages programmed through different schemes (TLC-program and MLC-program/SLC-program), then the memory device can accurately read data from all programming schemes, but the read performance deteriorates due to voltage switching overhead
Solution Approach 1:
The patent applies universality by designing a single read voltage that can universally read data from physical pages regardless of their programming scheme (TLC-program, MLC-program, or SLC-program). This eliminates the need for multiple dedicated read voltages and reduces voltage switching overhead, thereby improving read performance while maintaining accurate data retrieval from all programming schemes.
2Adaptability or versatility
If multiple read voltages are implemented to support different programming schemes, then data can be read from all page types, but the device complexity increases due to voltage generation and control circuits
Solution Approach 1:
The patent implements a universal read voltage that serves multiple programming schemes (TLC-program, MLC-program, SLC-program) without requiring separate voltage generation circuits for each scheme. This reduces the complexity of voltage generation and control circuits while maintaining adaptability to different programming schemes.
Solution Approach 2:
The patent changes the parameter of read voltage from multiple specialized voltages to a single universal voltage level. This parameter simplification reduces the complexity of voltage generation and control mechanisms while preserving the ability to read data from different programming schemes, thereby achieving both versatility and reduced complexity.
3Reliability
If read voltage is changed when switching between different programming schemes, then accurate reading is maintained, but the operation time increases due to voltage switching delays
Solution Approach 1:
The patent employs a universal read voltage that maintains reading accuracy across different programming schemes without requiring voltage changes during read operations. This eliminates voltage switching delays and reduces operation time, as the read voltage remains constant regardless of whether the physical page is TLC-programmed, MLC-programmed, or SLC-programmed.
Data Source
AI summary
A semiconductor memory device and a method of operating the same are provided herein. The semiconductor memory device includes first and second pages, a peripheral circuit, and a control logic. The first page includes first memory cells, each storing N bits. The second page includes second memory cells, each storing N−1 bit. The peripheral circuit performs a first program operation that results in a threshold voltage of each first memory cell to be included in one of 2N states and performs a second program operation that results in a threshold voltage of each second memory cell to be included in one of 2N−1 states. The control logic controls the first and second program operations through the peripheral circuit and controls the peripheral circuit to perform the second program operation by using at least one, but not all of a plurality of verify voltages that are used in the first program operation.