Semiconductor Blocking Layers Prevent Impurity Diffusion
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Solution Overview
Problem
Existing semiconductor devices face challenges in achieving high integration with improved word line current driving capability while minimizing the diffusion of conductivity-type impurities, which leads to increased leakage current and reduced integration efficiency.
Innovation Solution
The semiconductor device incorporates a blocking layer made of carbon or germanium, self-aligned with the lower interconnection, to prevent the diffusion of conductivity-type impurities, and uses selective epitaxial growth processes to form the word line and blocking layers, ensuring reduced impurity diffusion and enhanced current driving capability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Area of moving object
If the lower interconnection is reduced in size for high integration, then integration density is improved, but current driving capability deteriorates
Solution Approach 1:
The patent applies local quality by creating a doping concentration gradient in the lower interconnection, where the doping concentration is higher at the bottom portion near the blocking layer and lower at the top portion. This localized variation in doping concentration optimizes both current driving capability at the interface and overall integration density, resolving the contradiction between size reduction and power performance.
2Power
If doping concentration is increased to improve current driving capability, then power is improved, but impurity diffusion increases causing leakage current
Solution Approach 1:
The patent applies preliminary action by forming the blocking layer containing carbon or germanium before forming the lower interconnection. This pre-formed blocking layer acts as a diffusion barrier that prevents impurity diffusion during subsequent processing steps, allowing high doping concentrations to be used for current driving capability without the harmful side effect of impurity diffusion and leakage current.
Solution Approach 2:
The blocking layer serves as an intermediary substance between the lower interconnection and the surrounding structures. It mediates the contradiction by providing a diffusion barrier that allows the lower interconnection to maintain high doping concentrations for current driving capability while preventing impurity diffusion that would cause leakage current.
3Area of moving object
If vertical height of word line and active region is reduced for high integration, then integration density is improved, but manufacturing precision becomes more difficult
Solution Approach 1:
The patent applies self-service by using selective epitaxial growth to form the lower interconnection with self-aligned blocking layers. The epitaxial growth process automatically forms layers with precise thickness and alignment based on the underlying structure, reducing the need for additional patterning and alignment steps. This self-aligned formation method maintains manufacturing precision even as vertical dimensions are reduced for high integration.
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 significantly reduces off-current and improves electrical characteristics, allowing for higher integration density and reduced leakage current, even with reduced vertical height and width of the word line and active region.
Implementation Method 1
to prevent the diffusion of conductivity-type impurities
Implementation Method 2
uses selective epitaxial growth processes to form the word line and blocking layers
Data Source
AI summary
A semiconductor device includes a lower interconnection having second conductivity-type impurities on a substrate having first conductivity-type impurities. A switching device is on the lower interconnection. A first blocking layer is provided between the lower interconnection and the switching device. The first blocking layer includes carbon (C), germanium (Ge), or a combination thereof. A second blocking layer may be provided between the substrate and the lower interconnection.