Antiferroelectric Hafnium Oxynitride Charge Storage Layer
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Solution Overview
Problem
Current three-dimensional NAND flash memory devices face challenges in reducing the diameter of memory holes and thickness of charge storage layers, which limits the scaling down of memory cells and requires improved charge storage density to maintain data storage efficiency.
Innovation Solution
Incorporating an antiferroelectric hafnium oxide layer with specific crystal structures and nitrogen content in the charge storage layer, along with additional nitride layers to control nitrogen retention and enhance charge storage capacity, allowing for thinner layers and improved memory cell scaling.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If the diameter of the memory hole is reduced for scaling down, then memory cell size is reduced, but charge storage capacity decreases
Solution Approach 1:
The patent changes the chemical composition parameters of the charge storage layer by incorporating nitrogen into hafnium oxide to form hafnium oxynitride. This parameter change increases the charge storage density, allowing smaller memory holes to maintain or improve charge storage capacity despite reduced volume.
Solution Approach 2:
The patent uses composite materials by combining hafnium oxide with nitrogen to create hafnium oxynitride as the charge storage layer. This composite material provides higher charge storage density compared to conventional materials, enabling scaled-down memory cells to achieve required storage capacity.
2Length of stationary object
If the thickness of the charge storage layer is reduced for scaling down, then memory cell thickness is reduced, but charge storage density per unit thickness must increase
Solution Approach 1:
The patent modifies the charge storage layer composition to hafnium oxynitride, which has superior charge storage properties. This parameter change enables the layer to achieve higher charge storage density per unit thickness, allowing reduced thickness while maintaining required storage capacity.
3Quantity of substance
If nitrogen is added to enhance charge storage capacity, then charge storage density increases, but nitrogen loss during processing must be controlled
Solution Approach 1:
The patent introduces a nitrogen barrier layer as an intermediary structure to prevent nitrogen loss from the charge storage layer during subsequent processing steps. This barrier layer acts as a protective intermediary that retains nitrogen while allowing the charge storage layer to maintain high nitrogen content for enhanced storage density.
Solution Approach 2:
The nitrogen barrier layer is formed beforehand to prevent potential nitrogen loss during subsequent processing. This prior protective measure ensures that nitrogen remains retained in the charge storage layer throughout manufacturing processes, maintaining the desired charge storage density.
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
The solution significantly increases charge storage density, enabling the reduction of memory hole diameters and memory cell thickness, thereby enhancing memory capacity and data storage efficiency while maintaining effective erase characteristics.
Implementation Method 1
Incorporating an antiferroelectric hafnium oxide layer with specific crystal structures and nitrogen content in the charge storage layer
Implementation Method 2
along with additional nitride layers to control nitrogen retention and enhance charge storage capacity
Data Source
AI summary
A semiconductor memory device of an embodiment includes: a semiconductor layer; a gate electrode layer; a first insulating layer provided between the semiconductor layer and the gate electrode layer; a second insulating layer provided between the first insulating layer and the gate electrode layer; and an intermediate layer provided between the first insulating layer and the second insulating layer, the intermediate layer containing a first crystal of a space group Pbca (space group number 61), a space group P42/nmc (space group number 137), or a space group R-3m (space group number 166), and the intermediate layer containing hafnium (Hf), oxygen (O), and nitrogen (N).