Semiconductor Memory Device Side Wall Layer Oxygen Segmentation
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Solution Overview
Problem
In semiconductor memory devices with a VAL structure, the variable resistance layer causes leak current between word lines, leading to malfunction and increased power consumption due to its presence on both side surfaces of word lines and interlayer insulating layers.
Innovation Solution
A method of manufacturing a semiconductor memory device where a side wall layer with a higher proportion of oxygen atoms is formed between the interlayer insulating layers and the conductive layers, functioning as the variable resistance element, and an oxide layer with lower conductivity is placed between the interlayer insulating layers and the bit lines to suppress leak current.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If a variable resistance layer is provided on side surfaces of word lines and interlayer insulating layers in a VAL structure, then integration density is improved, but leak current between word lines increases
Solution Approach 1:
The side wall layer is divided into two distinct segments: a first side wall layer in contact with the interlayer insulating layer that prevents leak current, and a second side wall layer in contact with the bit line that forms the variable resistance element. This segmentation allows each segment to perform its specific function independently, resolving the contradiction between achieving high integration density and preventing leak current.
Solution Approach 2:
Different regions of the side wall layer are assigned different material compositions and properties. The first side wall layer has properties optimized for preventing leak current (higher oxygen content, different material composition), while the second side wall layer has properties optimized for forming the variable resistance element. This local differentiation of properties allows the structure to simultaneously achieve high integration density and prevent leak current.
2Productivity
If a variable resistance layer is provided on side surfaces of word lines and interlayer insulating layers, then memory cell array integration is improved, but power consumption increases
Solution Approach 1:
The side wall layer is segmented into functional regions, with the first side wall layer specifically designed to block leak current pathways between word lines. By isolating the variable resistance element to only where needed (at the bit line interface), the structure prevents parasitic current flow that would otherwise increase power consumption, while maintaining high integration density.
Solution Approach 2:
The harmful leak current path is extracted and eliminated by introducing the first side wall layer between the interlayer insulating layer and the variable resistance element. This extraction of the leak current pathway allows the memory cell array to achieve high integration without the associated power consumption penalty.
3Productivity
If a variable resistance layer is provided on side surfaces of word lines and interlayer insulating layers, then integration density is improved, but operational reliability deteriorates
Solution Approach 1:
The side wall layer is segmented into functional regions, with the first side wall layer specifically designed to block leak current pathways and the second side wall layer forming the variable resistance element. This segmentation ensures that the variable resistance element is precisely localized only where needed for memory operation, eliminating unwanted electrical interactions and improving operational reliability while maintaining high integration density.
Solution Approach 2:
The first side wall layer acts as an intermediary barrier between the interlayer insulating layer and the variable resistance element. This intermediary structure prevents direct electrical contact that would cause leak current and malfunction, thereby improving operational reliability while allowing the high-density VAL structure to function correctly.
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 configuration enhances integration density while reducing leak current and power consumption by isolating the variable resistance layer effectively, improving the operational reliability of memory cells.
Implementation Method 1
by migration of oxygen atoms between the side wall layer and the first conductive layers or migration of oxygen atoms between the side wall layer and the interlayer insulating layers, a proportion of oxygen atoms in the side wall layer adjacent to the interlayer insulating layers is made larger than a proportion of oxygen atoms in the side wall layer adjacent to the first conductive layers
Data Source
AI summary
First, a trench penetrating first conductive layers and interlayer insulating layers is formed. Next, a column-shaped conductive layer is formed to fill the trench via a side wall layer. Then, after formation of the side wall layer, by migration of oxygen atoms between the side wall layer and the first conductive layers or migration of oxygen atoms between the side wall layer and the interlayer insulating layers, a proportion of oxygen atoms in the side wall layer adjacent to the interlayer insulating layers is made larger than a proportion of oxygen atoms in the side wall layer adjacent to the first conductive layers, whereby the side wall layer adjacent to the first conductive layers is caused to function as the variable resistance element.