Silicon Nitride Barrier Layer for 3D NAND Hydrogen Diffusion
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Solution Overview
Problem
In three-dimensionally arranged NAND flash memories, hydrogen diffusion from the layer stack into the interconnect layer during thermal steps negatively affects the electrical properties of transistors, leading to deterioration.
Innovation Solution
A silicon nitride layer is introduced between the interconnect layer and the layer stack, acting as a barrier to prevent hydrogen diffusion, and is formed using a low-pressure chemical vapor deposition method to ensure it does not contribute to hydrogen diffusion itself.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If a layer stack is provided above an interconnect layer in a three-dimensionally arranged NAND flash memory, then the memory capacity and integration density are improved, but hydrogen diffusion from the layer stack into the interconnect layer during thermal steps causes deterioration of transistor electrical properties
Solution Approach 1:
A silicon nitride barrier layer is introduced between the layer stack and the interconnect layer to act as an intermediary that prevents hydrogen diffusion from the layer stack into the interconnect layer, thereby protecting the transistor electrical properties while maintaining the high-density three-dimensional structure
Solution Approach 2:
The silicon nitride barrier layer creates an inert environment that blocks hydrogen atoms, preventing them from diffusing into the interconnect layer during thermal processing steps, thus maintaining the electrical integrity of transistors in high-capacity 3D NAND structures
2Reliability
If a barrier layer is introduced between the interconnect layer and the layer stack to prevent hydrogen diffusion, then the electrical properties of transistors are protected, but the device structure and manufacturing process become more complex
Solution Approach 1:
The barrier layer is formed by changing the deposition parameters (low-pressure chemical vapor deposition) to ensure the material properties prevent hydrogen diffusion while maintaining compatibility with existing manufacturing processes, thus protecting transistor electrical properties without significantly increasing device complexity
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 solution effectively suppresses the deterioration of electrical properties in the interconnect layer by blocking hydrogen intrusion, maintaining the integrity of the transistors and improving the semiconductor device's performance.
Implementation Method 1
A silicon nitride layer is introduced between the interconnect layer and the layer stack, acting as a barrier to prevent hydrogen diffusion
Implementation Method 2
formed using a low-pressure chemical vapor deposition method to ensure it does not contribute to hydrogen diffusion itself
Data Source
AI summary
According to one embodiment, a semiconductor device includes a substrate, an interconnect layer, a layer stack, and a first silicon nitride layer. The interconnect layer includes a transistor provided on the substrate and a first interconnect electrically coupled to the transistor and is provided above the transistor. The layer stack is provided above the interconnect layer and includes conductive layers stacked with an insulation layer interposed between two of conductive layers of each pair of conductive layers. The first silicon nitride layer is provided between the interconnect layer and the layer stack.