Optimized Charge Storage in NAND Flash Memory: Patent-Based Insights
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Summary
Problems
In semiconductor devices, particularly NAND flash memories, the reduction in device size to increase memory capacity leads to challenges in charge storage film size, requiring higher charge capture density while preventing errors and maintaining retention characteristics, but existing methods like direct deposition of silicon nitride films result in nitriding and oxygen diffusion issues, reducing capture efficiency.
Innovation solutions
A semiconductor device and manufacturing method involving an amorphous silicon layer with added nitrogen, forming a silicon nitride layer at a controlled temperature, and a block insulating film structure to prevent nitriding and oxygen diffusion, enhancing charge capture density and retention characteristics.
TRIZ Analysis
Specific contradictions:
General conflict description:
Principle concept:
If the charge storage film size is reduced to increase memory capacity, then memory capacity increases, but charge capture efficiency deteriorates
Why choose this principle:
The patent applies local quality by creating a nitrogen concentration gradient within the charge storage film. The amorphous silicon layer has higher nitrogen concentration near the tunnel insulating film interface and lower concentration toward the control gate, optimizing charge capture at the critical interface region while maintaining film integrity throughout.
Principle concept:
If the charge storage film size is reduced to increase memory capacity, then memory capacity increases, but charge capture efficiency deteriorates
Why choose this principle:
The patent changes the nitrogen concentration parameter within the charge storage film by controlling nitrogen diffusion during thermal processing. By adjusting diffusion time and temperature, the nitrogen concentration profile is optimized to enhance charge capture efficiency in the reduced-size film structure.
Application Domain
Data Source
AI summary:
A semiconductor device and manufacturing method involving an amorphous silicon layer with added nitrogen, forming a silicon nitride layer at a controlled temperature, and a block insulating film structure to prevent nitriding and oxygen diffusion, enhancing charge capture density and retention characteristics.
Abstract
A semiconductor device of an embodiment can prevent nitriding of the lower-layer insulating film and oxygen diffusion from the upper-layer insulating film, so as to minimize the decrease in charge capture density. This semiconductor device includes a semiconductor layer, a first insulating film provided on the semiconductor layer, a nitrogen-added amorphous silicon layer formed on the first insulating film, a first silicon nitride layer formed on the amorphous silicon layer, and a second insulating film formed above the first silicon nitride layer.