Plasma-Assisted Phase Change Material Deposition
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Solution Overview
Problem
Conventional PVD processes for forming phase changeable material layers, such as GST, face challenges in controlling growth rate, density, and achieving a Face Centered Cubic (FCC) crystallization structure, leading to poor electrical characteristics and high costs due to difficulties in precisely controlling composition ratios and slow deposition rates.
Innovation Solution
A plasma-assisted chemical vapor deposition method is used to form phase changeable material layers by alternately depositing germanium, antimony, and tellurium layers, allowing for precise control of composition ratios and achieving a dense, FCC crystalline structure at low temperatures, improving electrical characteristics.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If conventional PVD process is used to form phase changeable material layer, then deposition can be performed, but growth rate control is difficult and layer density is poor
Solution Approach 1:
The patent changes the deposition parameters by using plasma-assisted chemical vapor deposition instead of conventional PVD. This allows precise control of growth rate through plasma power, gas flow rates, and temperature parameters while maintaining high deposition rates, resolving the contradiction between precision control and productivity
Solution Approach 2:
The patent replaces the mechanical physical vapor deposition process with a plasma-enhanced chemical vapor deposition process. This substitution enables better control over deposition kinetics through plasma chemistry, achieving both precise growth rate control and high deposition efficiency
2Manufacturing precision
If conventional PVD process is used to form phase changeable material layer, then deposition can be performed, but achieving FCC crystallization structure is difficult
Solution Approach 1:
The patent uses plasma temperature and chemical environment parameters to control crystallization structure formation. By adjusting plasma power, substrate temperature, and gas composition, the FCC crystallization structure is achieved with better control compared to conventional PVD
Solution Approach 2:
The patent introduces plasma as an intermediary that facilitates controlled crystallization. The plasma environment acts as a mediator between the deposited material and the substrate, enabling precise control over crystal structure formation without requiring complex post-deposition processing
3Manufacturing precision
If conventional PVD process is used to form GST layer, then deposition can be performed, but composition ratio control is very difficult
Solution Approach 1:
The patent segments the GST deposition into separate Ge, Sb, and Te layers deposited sequentially using plasma-enhanced CVD. This segmentation allows independent control of each element's composition and thickness, achieving precise overall composition ratio control while maintaining efficient production timing
Solution Approach 2:
The patent uses plasma as an intermediary that enables precise compositional control during deposition. The plasma environment allows for accurate control of reaction kinetics and material incorporation, achieving desired composition ratios without requiring extensive trial-and-error or post-processing adjustments
4Reliability
If conventional PVD process is used to form phase changeable material layer, then deposition can be performed, but electrical characteristics deteriorate
Solution Approach 1:
The patent changes the deposition parameters by using plasma-enhanced chemical vapor deposition, which produces denser layers with better crystallization. This results in superior electrical characteristics including lower resistance and better phase transition properties, while the process remains cost-effective compared to the high costs associated with achieving similar quality through conventional PVD
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 method enables the formation of phase changeable material layers with excellent electrical characteristics and density, overcoming the limitations of conventional PVD processes by allowing for precise control of composition ratios and reducing production costs and time.
Implementation Method 1
forming a plasma in a chamber having a substrate disposed therein, providing a first source gas including a germanium based material to form a first layer including the germanium based material on the substrate while maintaining the plasma in the chamber
Implementation Method 2
providing a second source gas including a tellurium based material to react with the first layer to form a first composite material layer including a germanium-tellurium composite material on the substrate while maintaining the plasma in the chamber
Data Source
AI summary
A phase changeable material layer usable in a semiconductor memory device and a method of forming the same are disclosed. The method includes forming a plasma in a chamber having a substrate disposed therein, providing a first source gas including a germanium based material to form a first layer including the germanium based material on the substrate while maintaining the plasma in the chamber, providing a second source gas including a tellurium based material to react with the first layer to form a first composite material layer including a germanium-tellurium composite material on the substrate while maintaining the plasma in the chamber, providing a third source gas including an antimony based material to form a second layer including the antimony based material on the first composite material layer while maintaining the plasma in the chamber, and providing a fourth source gas including tellurium based material to react with the second layer including antimony based material to form a second composite material layer including an antimony-tellurium composite material on the first composite material layer. Accordingly, the phase changeable material layer may be formed at a low temperature and power to have desirable electrical characteristics.