Tantalum Heat Generation Element Silicon Interface Durability
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Solution Overview
Problem
Heat generation elements used in CVD methods, particularly those made of tantalum, face durability issues due to weak creep strength at high temperatures, leading to fragility and potential peeling or void formation when carbonized, which affects their longevity and attachment to film forming apparatuses.
Innovation Solution
A heat generation element with a metallic tantalum core and a tantalum carbide peripheral layer, where the interface region has a higher silicon concentration, is manufactured using a vacuum chamber with silicon-containing hydrocarbon gas, allowing for enhanced durability and thermal stability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If tantalum wire is fully carbonized to enhance durability, then durability is improved, but the heat generation element becomes significantly fragile and handling becomes difficult
Solution Approach 1:
The patent applies local quality by creating a gradient carbon concentration distribution where the carbon content varies through the cross-section. The peripheral portion has higher carbon concentration for durability, while the inner portion maintains lower carbon concentration for flexibility and handling ease. This is achieved by controlling the carbonization process to penetrate only to a specific depth rather than fully carbonizing the entire wire.
2Ease of operation
If partial carbonization is performed to maintain handling ease, then handling is facilitated, but peeling or void generation occurs at the interface between tantalum carbide and metallic tantalum due to thermal expansion differences
Solution Approach 1:
The patent applies parameter changes by introducing silicon as an additional element that modifies the thermal and mechanical properties of the carbonized layer. Silicon addition changes the coefficient of thermal expansion and other parameters to better match between the carbonized peripheral portion and the metallic tantalum core, thereby preventing peeling and void formation during thermal cycling while maintaining the desired carbonization depth for handling ease.
3Productivity
If heating time is extended or temperature cycling is repeated, then film formation capacity increases, but peeling or void generation occurs around the interface due to thermal expansion differences
Solution Approach 1:
The patent applies the intermediary principle by introducing a silicon-containing carbonized layer as an intermediate zone between the metallic tantalum core and the outer carbonized layer. This intermediate layer with modified thermal properties acts as a buffer that accommodates thermal expansion differences during extended heating and repeated temperature cycling, preventing interface peeling and void formation while allowing sustained productivity.
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 heat generation element exhibits improved durability and resistance to thermal deformation, preventing peeling and void formation, and allowing for repeated use without significant deformation or loss of mechanical strength.
Implementation Method 1
electrifying and heating the tantalum wire
Implementation Method 2
decomposing material gas by bringing material gas into contact with a heat generation element
Implementation Method 3
introducing a silicon atom from an outer surface of the base material into an inside of the base material
Implementation Method 4
removing a natural oxide film formed on a tantalum surface in a vacuum heat treatment furnace
Data Source
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AI summary
An object of the disclosure is to provide a heat generation element having high durability and a method of manufacturing the same. A heat generation element 1 according to the disclosure includes a first layer 2 having a metallic tantalum phase, and a second layer 3 which covers a periphery of the first layer 2 and has a tantalum carbide phase, wherein a concentration of silicon in an interface portion 4 between the first layer 2 and the second layer 3 is higher than a concentration of silicon in a portion other than the interface portion 4.