Memory Hole Expansion in 3D Non-Volatile Storage Stacks
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
The miniaturization of memory cells in non-volatile storage devices poses a risk of memory holes being closed during the formation of memory films, preventing the semiconductor film from being formed within the holes and rendering the memory cell strings non-functional.
Innovation Solution
A non-volatile storage device design that includes a semiconductor pillar penetrating a stacked body with a memory film covering its periphery, where the memory film has a wider outer periphery between the stacked body and the semiconductor film, preventing the closure of memory holes and allowing for the deposition of a conductive material like polysilicon.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If memory cells are miniaturized to increase storage density, then storage capacity is improved, but the memory holes may close during memory film formation, preventing semiconductor film deposition and rendering memory cell strings non-functional
Solution Approach 1:
A memory hole expansion layer is formed at the bottom of the memory hole before memory film deposition. This preliminary structural preparation ensures that even when memory cells are miniaturized, the expansion layer maintains an open pathway for memory film and semiconductor film deposition, preventing hole closure and ensuring functional memory cell strings.
2Quantity of substance
If memory cells are miniaturized to increase storage density, then storage capacity is improved, but manufacturing yield decreases due to memory hole closure
Solution Approach 1:
The memory hole expansion layer is prepared in advance before memory film formation. This preliminary action ensures that memory holes remain open during subsequent processing steps, preventing manufacturing defects and improving yield without sacrificing storage density.
3Reliability
If the outer periphery of the memory film is made wider to prevent hole closure, then reliability is improved, but device complexity increases
Solution Approach 1:
The memory hole expansion layer is selectively formed only at the bottom of the memory hole where it is most needed to prevent closure. This localized approach provides the necessary structural support and opens space without unnecessarily increasing the complexity of the entire memory device structure.
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 design enhances the yield of manufacturing non-volatile storage devices by preventing memory hole closure, ensuring the formation of functional memory cell strings and improving the reliability and electrical connection of memory cells.
Implementation Method 1
a memory film which covers a periphery of the semiconductor film
Implementation Method 2
a semiconductor film is formed on the memory film in the memory hole
Data Source
AI summary
According to an embodiment, a non-volatile storage device includes a first layer, a second layer formed on the first layer, a stacked body including a plurality of conductive films stacked on the second layer, and a semiconductor pillar which penetrates the stacked body and the second layer and reaches the first layer. The semiconductor pillar includes a semiconductor film formed along an extending direction of the semiconductor pillar, and a memory film which covers a periphery of the semiconductor film. The memory film includes a first portion formed between the stacked body and the semiconductor film and a second portion formed between the second layer and the semiconductor film. An outer periphery of the second portion in a plane perpendicular to the extending direction is wider than an outer periphery of the first portion on a second layer side of the stacked body.