Thermoelectric Layer Production via Elemental Target Sputtering
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Solution Overview
Problem
Current thermoelectric generators have low efficiency due to suboptimal Seebeck coefficients and limited power generation capabilities, primarily because of the inefficiencies in producing thermoelectric layers through reactive sputtering and the thickness limitations of single-crystal layers produced by conventional sputtering.
Innovation Solution
The method involves producing thermoelectric targets by mixing powdered starting materials with particle sizes between 0.5-150 μm under energy input and using magnetron sputter deposition to create layers with increased grain boundaries, resulting in higher Seebeck coefficients and improved electrical and thermal conductivities, allowing for thicker layers that generate more power without sacrificing properties.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If reactive sputtering is used to produce thermoelectric layers, then the layers are deposited with chemical compounds formed by exothermic reactions, but the additional heat input causes in-situ heat treatment that decreases grain boundaries and reduces Seebeck coefficient
Solution Approach 1:
The patent extracts the harmful exothermic chemical reactions from the deposition process by using elemental targets instead of compound targets. This eliminates the in-situ heat treatment that occurs during reactive sputtering, preserving grain boundaries and maintaining high Seebeck coefficients in the deposited layers.
Solution Approach 2:
The patent changes the chemical composition parameter of the targets from compounds to elements. By using elemental targets (Bi, Te, Se, Sb) instead of compound targets, the deposition process no longer involves exothermic chemical reactions, thereby eliminating the unwanted heat input and in-situ tempering effect.
2Reliability
If conventional sputtering is used to achieve high degree of crystallization, then conductivity increases, but layer thickness must be limited to 5 μm to maintain crystallization quality
Solution Approach 1:
The patent removes the exothermic chemical reactions from the deposition process, which eliminates the in-situ heat treatment that limits layer thickness. This allows thicker layers to be deposited while maintaining good crystallization quality, as the harmful thermal effect is extracted from the process.
Solution Approach 2:
The patent changes the deposition conditions by using elemental targets and controlling the deposition parameters to achieve optimal crystallization in thicker layers. The Seebeck coefficient is optimized by controlling grain boundary formation through deposition parameter adjustment rather than through post-deposition heat treatment.
3Power
If thicker layers are deposited to generate more power, then current flow capability improves, but degree of crystallization decreases in conventional sputtering
Solution Approach 1:
The patent extracts the harmful thermal effect from the deposition process, allowing thicker layers to be deposited without the degradation of crystallization quality that normally occurs. This enables thicker layers that can carry more current and generate more power while maintaining good thermoelectric properties.
4Ease of manufacture
If reactive sputtering with compound targets is used, then thermoelectric layers are produced, but the process complexity and target production complexity increase
Solution Approach 1:
The patent extracts the chemical compound formation step from the target material, using elemental targets instead. This simplifies target production and eliminates the need for complex reactive sputtering processes, while still achieving high-quality thermoelectric layers through controlled deposition of elemental materials.
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 Seebeck coefficient and efficiency of thermoelectric generators, enabling higher power generation and improved adhesion and homogeneity of the layers, while reducing brittleness and incorporating fewer foreign atoms, thus overcoming previous limitations on layer thickness and efficiency.
Implementation Method 1
depositing the thermoelectric material from the target onto the substrate by means of magnetron sputter deposition
Implementation Method 2
the target of thermoelectric material is produced by mixing at least two starting materials in the foam of powders with a particle size in the range of 0.5-150 μm under the input of energy
Data Source
AI summary
The invention relates to a method for producing thermoelectric layers by depositing thermoelectric material on a substrate by means of sputter deposition. In order to create a method for producing thermoelectric layers that are better suited for use in thermogenerators, and in particular have higher Seebeck coefficients, the production of a target made of thermoelectric material is proposed by mixing at least two powdered starting materials having a particle size from 0.01 μm-5000 μm, while coupling in energy and depositing the thermoelectric material from the target on the substrate by way of magnetron sputter deposition.