Nanoparticle Charge Trapping Layer for Memory Retention
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Solution Overview
Problem
Charge-trapping non-volatile memory devices face challenges with insufficient data retention time due to inadequate density and uniformity of charge trapping sites in the silicon nitride layer, which also complicates miniaturization and increases operating voltages.
Innovation Solution
A charge-trapping layer is developed using high-density, uniformly sized nanoparticles surrounded by silicon nitride, formed through a method involving linker bonding, metal ion transformation, and nitride supplementation, which enhances charge trapping efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the silicon nitride layer thickness is increased to improve charge trapping density and data retention, then data retention is improved, but memory cell height increases and miniaturization is hindered
Solution Approach 1:
The charge trapping function is segmented from the bulk silicon nitride layer to discrete silicon nitride nanoparticles. These nanoparticles are distributed throughout the oxide layer, allowing charge trapping capability to be maintained without requiring a thick continuous silicon nitride layer, thus reducing overall memory cell height while preserving data retention
Solution Approach 2:
Instead of using a uniform thick silicon nitride layer throughout, the invention concentrates silicon nitride in the form of nanoparticles at specific locations within the oxide layer. This localized approach provides sufficient charge trapping sites without increasing the overall layer thickness, enabling miniaturization while maintaining reliability
2Reliability
If the silicon nitride layer thickness is increased to ensure sufficient charge trapping sites, then charge trapping capability is improved, but operating voltage increases and operating speed decreases
Solution Approach 1:
The continuous silicon nitride charge trapping layer is segmented into discrete nanoparticles dispersed in the oxide layer. This segmentation reduces the overall amount of silicon nitride material needed, lowering the electric field strength required for charge tunneling and thus reducing operating voltage while maintaining adequate charge trapping capability
Solution Approach 2:
The invention changes the physical state and distribution parameters of silicon nitride from a continuous thick layer to discrete nanoparticles with controlled size and density. This parameter change optimizes the charge trapping efficiency per unit thickness, enabling sufficient charge trapping at lower operating voltages and improved operating speed
3Ease of manufacture
If conventional charge trapping layers are used, then manufacturing is simpler, but charge trapping site density and uniformity are insufficient
Solution Approach 1:
Metal ions are preliminarily distributed throughout the oxide layer before forming the final charge trapping structure. This preliminary distribution ensures uniform spatial arrangement of future nanoparticle sites, and when converted to silicon nitride nanoparticles, this results in uniform charge trapping site density without requiring complex post-processing steps
Solution Approach 2:
Metal ions serve as an intermediary material that facilitates the formation of uniformly distributed silicon nitride nanoparticles. The metal ions are easily deposited and distributed uniformly, and then transformed into silicon nitride nanoparticles through chemical reactions, thereby achieving high uniformity while maintaining manufacturing simplicity
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This solution allows for scaled-down memory devices with improved power consumption, stability, reproducibility, and reliability, while maintaining excellent data retention and preventing charge loss even when the tunneling layer is damaged.
Implementation Method 1
bonding metal ions to the linkers; transforming the metal ions into metallic nanoparticles by applying energy to the metallic nanoparticles
Data Source
Figure 1~2A
Figure 2B~2C
Figure 2D~2E
AI summary
A non-volatile memory device that includes: a charge trapping layer for trapping charges, wherein the charge trapping layer includes: a linker layer (120) formed over a substrate (112) and including linkers (L) to be bonded to metal ions; metallic nanoparticles (140) formed out of the metal ions over the linker layer; and a nitride (150) filling gaps between the metallic nanoparticles.