Charge-Trapping Memory Cells with Trap-Enhancing Additives
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Solution Overview
Problem
Charge-trapping-materials in memory cells often have too many shallow traps, leading to poor charge retention.
Innovation Solution
Incorporating trap-enhancing-additives such as carbon, boron, phosphorus, or metal into the charge-trapping-material to modify trap depths and improve charge retention.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional charge-trapping-material is used in memory cells, then the material can store charge, but the charge retention is poor due to too many shallow traps
Solution Approach 1:
The patent changes the chemical composition parameters of the charge-trapping-material by incorporating specific additives (e.g., carbon at 1-20 at%, boron at 1-20 at%, phosphorus at 1-20 at%, or metal atoms at 0.1-10 at%) to modify the trap depth distribution. This transforms the material properties from having many shallow traps to having deeper traps with improved charge retention characteristics.
Solution Approach 2:
The patent creates a composite charge-trapping-material system by combining conventional materials (silicon nitride, silicon oxynitride, or metal oxides) with trap-enhancing additives. This composite approach leverages the charge storage capability of the base material while the additive provides deeper trap states, achieving both sufficient trap density and improved charge retention.
2Reliability
If trap-enhancing-additive is incorporated into charge-trapping-material, then charge retention is improved, but the device complexity increases
Solution Approach 1:
The patent applies local quality by introducing trap-enhancing-additive at specific concentration ranges (e.g., carbon 1-20 at%, boron 1-20 at%, phosphorus 1-20 at%, metal 0.1-10 at%) within the charge-trapping-material matrix. This localized modification of material composition achieves the desired trap depth enhancement without requiring complete redesign of the entire material system.
Solution Approach 2:
The patent manages complexity by precisely controlling additive concentration parameters within optimal ranges. By specifying narrow concentration windows (e.g., 1-20 at% for carbon/boron/phosphorus, 0.1-10 at% for metals), the patent achieves improved charge retention while maintaining manufacturability and avoiding excessive material complexity.
Data Source
AI summary
Some embodiments include a memory cell having charge-trapping-material between a semiconductor channel material and a gating region. The charge-trapping-material includes silicon, nitrogen and trap-enhancing-additive. The trap-enhancing-additive includes one or more of carbon, phosphorus, boron and metal. Some embodiments include an integrated assembly having a stack of alternating first and second levels. The first levels include conductive structures and the second levels are insulative. Channel-material-pillars extend through the stack. Charge-trapping-regions are along the channel-material-pillars and are between the channel-material-pillars and the conductive structures. The charge-trapping-regions include a charge-trapping-material which contains silicon, nitrogen and trap-enhancing-additive. The trap-enhancing-additive includes one or more of carbon, phosphorus, boron and metal.