Source Contact Spacer Structure for 3D Memory Reliability
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Solution Overview
Problem
The challenge of improving the degree of integration and operational reliability of semiconductor devices is addressed by stacking memory cells in three dimensions, where existing structures face limitations in achieving stable and reliable performance.
Innovation Solution
A semiconductor device structure is developed with a gate structure comprising conductive layers alternately stacked with insulating layers, featuring a source contact structure surrounded by nitride and oxide spacers, which facilitate hydrogen and fluorine gas passage, enhancing reliability through controlled diffusion pathways.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If memory cells are stacked in three dimensions to improve degree of integration, then integration density increases, but structural stability and operational reliability deteriorate
Solution Approach 1:
The patent implements a multi-layer spacer structure where an oxide spacer is positioned within a nitride spacer, creating a nested configuration. This nested design provides enhanced structural support for the stacked memory cells while maintaining compact dimensions, thereby improving both integration density and structural stability simultaneously
Solution Approach 2:
The patent employs a composite spacer structure combining oxide and nitride materials with different properties. The oxide layer provides structural support and mechanical strength, while the nitride layer offers chemical stability and diffusion barrier properties. This composite approach enhances overall device reliability while maintaining the three-dimensional stacked architecture for high integration
2Ease of manufacture
If conventional single-layer spacer structures are used, then manufacturing is simpler, but diffusion control and passivation effectiveness are insufficient
Solution Approach 1:
The patent divides the spacer function into multiple segments with different materials (oxide and nitride layers) positioned at different locations. The oxide spacer is formed first, followed by the nitride spacer surrounding it. This segmentation allows each layer to perform its specific function optimally while maintaining a manufacturable multi-step process
3Ease of manufacture
If no diffusion barrier structures are implemented, then manufacturing is easier, but damage to surrounding layers from hydrogen and fluorine gas increases
Solution Approach 1:
The oxide and nitride spacers serve as intermediary diffusion barrier structures between the processing environment and the sensitive device layers. These spacers control and mediate the diffusion of hydrogen and fluorine gases, allowing necessary process gases to pass while preventing harmful concentrations from damaging surrounding layers, thus protecting the device without complicating the manufacturing process
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 proposed structure improves integration and reliability by allowing controlled diffusion of hydrogen and fluorine gases, reducing damage to surrounding layers and enhancing passivation effects, thereby stabilizing the semiconductor device performance.
Implementation Method 1
allowing controlled diffusion of hydrogen and fluorine gases
Implementation Method 2
forming an oxide liner within the opening; forming a nitride liner along a surface of the oxide liner
Data Source
AI summary
A semiconductor device may include: a gate structure including a plurality of conductive layers alternately stacked with a plurality of insulating layers; a source contact structure extending through the gate structure; a nitride spacer surrounding a first end of the source contact structure; and an oxide spacer surrounding the nitride spacer and a second end of the source contact structure.