Susceptor Recesses for Multi-Material Sublimation
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Solution Overview
Problem
Conventional methods for depositing multiple materials, such as cadmium telluride (CdTe) with other materials for photovoltaic cells, are limited by different melting points and vapor pressures, making co-deposition challenging, especially with time-consuming co-evaporation processes being unsuitable for certain applications.
Innovation Solution
A deposition system using co-sublimation processes with a susceptor having spatially separated recesses for different materials, where each material is heated to a specific temperature, allowing for simultaneous sublimation and deposition on a substrate, with thermal insulation and adjustable vapor pressure control to enhance the deposition process.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If conventional close spaced sublimation (CSS) and vapor transport (VTM) processes are used, then deposition of materials can be achieved, but co-deposition of CdTe with other materials is not possible due to different melting points and vapor pressures
Solution Approach 1:
The susceptor is divided into multiple separate recesses, each accommodating a different material. This segmentation allows each material to be heated and sublimed independently at its optimal temperature, enabling co-deposition of materials with different melting points and vapor pressures while maintaining precise compositional control.
Solution Approach 2:
Each recess in the susceptor is designed with specific thermal insulation properties and heating characteristics tailored to the material it contains. This local quality optimization ensures that each material sublimes at its appropriate rate, achieving both co-deposition capability and precise material composition control.
2Adaptability or versatility
If co-evaporation process is used, then CdTe can be co-deposited with other materials, but the process is inherently time-consuming
Solution Approach 1:
The process transitions from evaporation to sublimation, changing the physical mechanism of material transfer. By heating materials to their sublimation temperatures in separate recesses, the process achieves faster deposition rates compared to co-evaporation, while still enabling co-deposition of multiple materials with different thermal properties.
Solution Approach 2:
Materials are pre-positioned in separate recesses on the susceptor before the deposition process begins. This preliminary arrangement allows all materials to be heated and sublimed simultaneously during a single process run, significantly reducing total deposition time compared to sequential evaporation methods.
3Manufacturing precision
If multiple materials are deposited using conventional methods, then deposition can occur, but precise temperature control for each material is not achievable
Solution Approach 1:
The susceptor is segmented into multiple isolated recesses, each capable of independent temperature control. This physical segmentation allows precise temperature control for each material without requiring complex multi-zone heating systems, as each recess acts as an independent thermal zone.
Solution Approach 2:
The susceptor with its recesses acts as an intermediary structure that simplifies temperature control. By providing pre-defined thermal zones through the recess design, the system achieves precise temperature control for multiple materials without the complexity of independently controlled heating elements for each material position.
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
Enables efficient co-deposition of multiple materials, improving the formation of solar cells by allowing for precise temperature control and vapor pressure adjustment, thereby enhancing the properties of thin film solar cells like CdTe films.
Implementation Method 1
a heater for heating the cadmium telluride and the other materials to sublime
Implementation Method 2
a thermal insulation layer on the susceptor between the recesses
Data Source
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AI summary
A system (10) for depositing two or more materials on a substrate (100) is provided. The system (10) comprises one or more susceptors (11) configured to define two or more recesses (12) for accommodating at least a first material (13) and a second material (14) respectively. The first and second materials (13, 14) are different. The system (10) further comprises one or more heaters for heating the first material (13) and the second material (14) for sublimation of the first and second materials (13, 14) for deposition on the substrate (100). A method for depositing two or more materials on a substrate (100) is also presented.