3D NAND Electrode Film Segmentation for Leakage Control
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Solution Overview
Problem
In semiconductor memory devices with a three-dimensional structure, the increasing integration density leads to a decrease in the distance between electrode films, causing leak currents and potentially shorting issues, which can result in increased resistance values and decreased writing speed, ultimately leading to memory operation failures.
Innovation Solution
The semiconductor memory device design includes a stacked body with alternately layered insulating and electrode films, where the electrode films are structured with a main body and a second portion extending beyond the barrier metal layer, preventing shorting and maintaining a larger volume to reduce resistance, and the manufacturing process involves selective growth and etching techniques to form the electrode films and barrier metal layer.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the integration degree of the semiconductor memory device is increased, then the electrode films can be made more compact, but the distance between electrode films decreases causing leak current and shorting issues
Solution Approach 1:
The electrode film is divided into multiple segments along the stacking direction, with insulating films positioned between adjacent electrode films. This segmentation prevents direct electrical contact between electrode films while maintaining compact integration, thereby reducing leak current and shorting risks without sacrificing integration density.
2Reliability
If metal material is removed from grooves to prevent shorting, then leak current is reduced, but the volume of electrode films decreases causing increased resistance and decreased writing speed
Solution Approach 1:
An insulating film is introduced as an intermediary layer between adjacent electrode films. This insulating film prevents direct electrical contact and shorting between electrode films while allowing the electrode films to maintain their full volume and conductivity, thus preventing leak current without increasing resistance or decreasing writing speed.
3Productivity
If electrode films are made thinner to reduce distance, then integration density improves, but resistance increases and writing speed decreases
Solution Approach 1:
The electrode films are arranged in the stacking direction (vertical dimension) rather than only in the planar direction. This three-dimensional arrangement allows integration density to increase without reducing the thickness or volume of individual electrode films, maintaining low resistance and high writing speed while achieving higher integration density through vertical stacking.
Data Source
AI summary
According to one embodiment, a semiconductor memory device includes a substrate, a stacked body, and a columnar part. The stacked body is provided on the substrate. The stacked body includes a plurality of first insulating films and a plurality of electrode films alternately stacked one layer by one layer. The columnar part includes a semiconductor pillar provided in the stacked body and extending in a stacking direction of the stacked body, and a memory film provided between the semiconductor pillar and the stacked body. The electrode films include a first portion provided on a side part of the columnar part, a second part contacting the first portion and provided further outside the columnar part, and a first conductive layer covering an upper surface and a lower surface of the first portion.