Semiconductor Memory Device Silicon Nitride Barrier Layer Fluorine Diffusion
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Solution Overview
Problem
Existing semiconductor memory devices face challenges in suppressing the diffusion of impurities like fluorine, which can lead to void generation in inter-layer insulating layers, affecting the potential distribution and characteristics of memory cells.
Innovation Solution
Incorporating a silicon nitride layer between the barrier metal layer and the inter-layer insulating layer, and providing separate silicon nitride layers on the upper and lower surfaces of the conductive layer, to prevent fluorine diffusion and void formation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If a barrier metal layer is used to prevent impurity diffusion, then impurity diffusion is suppressed, but void generation occurs in the inter-layer insulating layer
Solution Approach 1:
A silicon nitride layer is introduced as an intermediary barrier between the metal layer and the inter-layer insulating layer. This intermediate layer prevents direct contact and reaction between the barrier metal and the insulating layer, thereby suppressing void generation while maintaining impurity diffusion prevention capabilities
Solution Approach 2:
The structure employs a composite material system consisting of multiple layers with different properties: the barrier metal layer for impurity diffusion prevention, the silicon nitride layer for void suppression, and the inter-layer insulating layer for electrical isolation. This composite structure resolves the contradiction by combining materials with complementary functions
2Device complexity
If the structure is simplified without additional layers, then manufacturing complexity is reduced, but impurity diffusion and void generation cannot be simultaneously suppressed
Solution Approach 1:
The barrier structure is segmented into distinct functional layers: the barrier metal layer for impurity diffusion prevention and the silicon nitride layer for void suppression. This segmentation allows each layer to perform its specific function optimally without compromising the other, achieving reliable impurity and void control
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 effectively suppresses void generation in the inter-layer insulating layer, ensuring uniform potential distribution and improved memory cell characteristics.
Implementation Method 1
Incorporating a silicon nitride layer between the barrier metal layer and the inter-layer insulating layer, and providing separate silicon nitride layers on the upper and lower surfaces of the conductive layer, to prevent fluorine diffusion and void formation
Data Source
AI summary
According to an embodiment, a semiconductor memory device comprises: a stacked body including control gate electrodes stacked upwardly of a substrate; a semiconductor layer facing the control gate electrodes; and a gate insulating layer provided between the control gate electrode and the semiconductor layer. The stacked body comprises: a first metal layer configuring the control gate electrode; a first barrier metal layer contacting an upper surface of this first metal layer; a first silicon nitride layer contacting an upper surface of this first barrier metal layer; a first inter-layer insulating layer contacting an upper surface of this first silicon nitride layer; a second barrier metal layer contacting a lower surface of the first metal layer; a second silicon nitride layer contacting a lower surface of this second barrier metal layer; and a second inter-layer insulating layer contacting a lower surface of this second silicon nitride layer.