Unlock instant, AI-driven research and patent intelligence for your innovation.

Sequential deselection of word lines to suppress first read issues

An unselected, first-time technology, applied in semiconductor memory, semiconductor field

Active Publication Date: 2021-12-10
SANDISK TECH LLC
View PDF0 Cites 0 Cited by
  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

However, as process geometries shrink, there are many design and process challenges
These challenges include increased variability in transistor characteristics with process, voltage, and temperature variations

Method used

the structure of the environmentally friendly knitted fabric provided by the present invention; figure 2 Flow chart of the yarn wrapping machine for environmentally friendly knitted fabrics and storage devices; image 3 Is the parameter map of the yarn covering machine
View more

Image

Smart Image Click on the blue labels to locate them in the text.
Viewing Examples
Smart Image
  • Sequential deselection of word lines to suppress first read issues
  • Sequential deselection of word lines to suppress first read issues
  • Sequential deselection of word lines to suppress first read issues

Examples

Experimental program
Comparison scheme
Effect test

Embodiment Construction

[0028] Techniques are described for eliminating or reducing electrons trapped within a NAND string after performing a sensing operation using a NAND string (eg, a read operation or a program verify operation) or at the end of a sensing operation. In some cases, during the second read operation following the first read operation, the memory cell transistor's vibrations are caused by trapped electrons at the thin oxide / polysilicon interface of the memory cell transistor generated at the end of the first read operation. Variations in threshold voltage, first read problems may occur. In one example, as word lines connected to unselected memory cell transistors of a NAND string are deselected after a sensing operation, a high threshold voltage (VT) state (e.g., C state, G state, or highest programmed state ) memory cell transistors may cause the channel of the NAND string to become cut off during discharge and cause the channel of the NAND string to couple down to the word line due...

the structure of the environmentally friendly knitted fabric provided by the present invention; figure 2 Flow chart of the yarn wrapping machine for environmentally friendly knitted fabrics and storage devices; image 3 Is the parameter map of the yarn covering machine
Login to View More

PUM

No PUM Login to View More

Abstract

A system and method for reducing trapped electrons within a NAND string is described. During a sensing operation, one or more control circuits may start with the first set of consecutive memory cell transistors closest to the first end of the NAND string and start with the consecutive memory cell transistors closest to the second end of the NAND string. The sequence at which the second set of cell transistors ends, discharging the control gates corresponding to consecutive memory cell transistors of the NAND string from a read pass voltage (e.g., 10V) to a second voltage less than the pass voltage (e.g., 2V) or initiates its discharge. Subsequently, one or more control circuits may discharge the control gates corresponding to successive memory cell transistors from the second voltage to a third voltage less than the intermediate voltage (eg, from 2V to 0V), either concurrently or simultaneously.

Description

technical field [0001] The present application relates to the field of semiconductors, in particular, to the field of semiconductor memory. Background technique [0002] Semiconductor memory is widely used in various electronic devices, such as cellular telephones, digital cameras, personal digital assistants, medical electronics, mobile computing devices, and non-mobile computing devices. Semiconductor memory may include nonvolatile memory or volatile memory. Non-volatile memory allows storage and retention of information even when the non-volatile memory is not connected to a power source (eg, a battery). Examples of non-volatile memory include flash memory (eg, NAND-type and NOR-type flash memory), electrically erasable programmable read-only memory (EEPROM), ferroelectric memory (eg, FeRAM), magnetoresistive memory ( For example, MRAM), and phase change memory (for example, PRAM or PCM). Nonvolatile memory can use floating gate transistors or charge trapping transisto...

Claims

the structure of the environmentally friendly knitted fabric provided by the present invention; figure 2 Flow chart of the yarn wrapping machine for environmentally friendly knitted fabrics and storage devices; image 3 Is the parameter map of the yarn covering machine
Login to View More

Application Information

Patent Timeline
no application Login to View More
Patent Type & Authority Patents(China)
IPC IPC(8): G11C16/16G11C16/26G11C16/34G11C16/10G11C16/04G11C16/30G11C16/08
CPCG11C16/0483G11C16/08G11C16/10G11C16/16G11C16/26G11C16/30G11C16/3427G11C16/3459
Inventor 光平规之赖军宏
Owner SANDISK TECH LLC