Molybdenum Electrode Chlorine Gradient for Impurity Diffusion Control
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Solution Overview
Problem
The diffusion of impurity elements through crystal grain boundaries in semiconductor devices with molybdenum electrode layers poses a challenge, affecting the properties and reliability of semiconductor memory devices.
Innovation Solution
A semiconductor device with a molybdenum electrode layer featuring a chlorine concentration gradient is introduced, where the chlorine concentration is higher near the insulating layer and decreases further away, formed using a two-stage temperature control process during atomic layer deposition, resulting in larger crystal grain sizes and reduced impurity diffusion.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a molybdenum electrode layer is used in semiconductor devices, then the device can achieve desired electrical properties, but impurity elements diffuse through crystal grain boundaries during manufacturing, degrading device performance
Solution Approach 1:
The patent changes the physical and chemical parameters of the molybdenum electrode layer by forming a chlorine concentration gradient through two-stage temperature control during atomic layer deposition. This parameter change transforms the uniform structure into a gradient structure with higher chlorine concentration near the insulating layer interface, which stabilizes the electrode layer and prevents impurity diffusion through crystal grain boundaries, thereby resolving the contradiction between maintaining electrical properties and preventing harmful impurity diffusion
Solution Approach 2:
The patent applies local quality by creating a non-uniform chlorine distribution within the molybdenum electrode layer. The chlorine concentration is locally higher near the insulating layer interface and decreases toward the upper portion of the electrode layer. This localized variation in composition provides different functional properties at different depths: the chlorine-rich region near the interface prevents impurity diffusion and stabilizes threshold voltage, while the upper region maintains good electrical conductivity
2Ease of manufacture
If the electrode layer is formed with standard single-stage deposition, then the manufacturing process is simple, but the crystal grain size remains small leading to increased impurity diffusion paths
Solution Approach 1:
The patent employs periodic action by using two-stage temperature control during the atomic layer deposition process. The first stage uses a lower temperature to form the initial portion of the electrode layer with specific chlorine incorporation, while the second stage uses a higher temperature to complete the deposition with different chlorine concentration characteristics. This periodic variation in deposition conditions creates the desired chlorine concentration gradient and larger crystal grain sizes without significantly complicating the manufacturing process
Solution Approach 2:
The patent changes the temperature parameter during the deposition process to control crystal grain growth. By implementing two-stage temperature control with different temperature levels, the process promotes larger crystal grain formation compared to single-stage deposition. This parameter change achieves better control over crystal grain size and chlorine distribution, reducing impurity diffusion paths while maintaining manufacturing feasibility
3Ease of manufacture
If uniform chlorine distribution is maintained in the electrode layer, then the manufacturing process is straightforward, but the threshold voltage remains unstable and data retention is poor
Solution Approach 1:
The patent applies local quality by creating a non-uniform chlorine distribution within the molybdenum electrode layer. The chlorine concentration is locally higher near the insulating layer interface and decreases toward the upper portion of the electrode layer. This localized variation in composition provides different functional properties at different depths: the chlorine-rich region near the interface prevents impurity diffusion and stabilizes threshold voltage, while the upper region maintains good electrical conductivity
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 approach enhances the properties of semiconductor memory devices by stabilizing the threshold voltage and improving data retention, while preventing impurity diffusion and reducing defects in the electrode layer.
Implementation Method 1
The electrode layer has a chlorine concentration gradient such that a first concentration of chlorine in a first portion of the electrode layer closer to the insulating layer is higher than a second concentration of chlorine in a second portion of the electrode layer less closer to the insulating layer
Implementation Method 2
formed using a two-stage temperature control process during atomic layer deposition
Data Source
AI summary
A semiconductor device includes a substrate and an insulating film formed on the substrate, and an electrode layer comprising molybdenum, formed in contact with the insulating film. The electrode layer has a chlorine concentration gradient such that a first concentration of chlorine in a first portion of the electrode layer closer to the insulating layer is higher than a second concentration of chlorine in a second portion of the electrode layer less closer to the insulating layer.