US Patent Application 17828685. NON-VOLATILE MEMORY WITH ENGINEERED CHANNEL GRADIENT simplified abstract
Contents
NON-VOLATILE MEMORY WITH ENGINEERED CHANNEL GRADIENT
Organization Name
Inventor(s)
Jiacen Guo of Sunnyvale CA (US)
Xiang Yang of Santa Clara CA (US)
Xiaochen Zhu of Milpitas CA (US)
NON-VOLATILE MEMORY WITH ENGINEERED CHANNEL GRADIENT - A simplified explanation of the abstract
This abstract first appeared for US patent application 17828685 titled 'NON-VOLATILE MEMORY WITH ENGINEERED CHANNEL GRADIENT
Simplified Explanation
The patent application describes a method to save power during the read process in NAND memory.
- NAND strings in each sub-block of a block have independently controlled source side select lines and drain side select lines.
- Unselected sub-blocks have floating NAND strings, which do not draw current.
- To prevent read disturb in unselected sub-blocks, nearby unselected word lines are lowered to intermediate voltages while the selected word line is lowered.
- This creates a channel potential gradient in the floated NAND strings of unselected sub-blocks that avoids read disturb.
- The selected word line is then raised to the appropriate read compare voltage for sensing the selected memory cells.
Original Abstract Submitted
To save power during a read process, NAND strings of each sub-block of a block have independently controlled source side select lines connected to source side select gates and drain side select lines connected to drain side select gates so that NAND strings of unselected sub-blocks can float and not draw current. To prevent read disturb in NAND strings of unselected sub-blocks, after all word lines are raised to a pass gate voltage, unselected word lines nearby the selected word line are lowered to respective intermediate voltages while lowering the voltage on the selected word line in order to achieve a channel potential gradient in the floated NAND strings of the unselected sub-blocks that does not result in read disturb. Subsequently, the selected word line is raised to the appropriate read compare voltage so the selected memory cells can be sensed.
