Vacuum Coating Inner Chamber Temperature Control for Perovskite Deposition
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Solution Overview
Problem
Conventional reactive vapor phase deposition methods for perovskite layers face challenges in process control, particularly with substances having low evaporation temperatures, leading to inaccurate and reproducibility issues, and create corrosive atmospheres that require specialized chamber materials and pose safety risks for operators.
Innovation Solution
A coating device with a temperature-controlled inner chamber surrounding the vapor section between the evaporator and substrate holder, allowing for precise temperature control below the evaporation temperature of the material, reducing re-evaporation, and incorporating heat exchanger and active heating evaporator sources for independent temperature adjustment of precursor substances.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If the organic precursor is evaporated by heating the evaporator source, then the material is deposited on the substrate, but the partial pressure in the vacuum chamber sharply increases and uncontrolled deposition occurs on all chamber surfaces
Solution Approach 1:
The vacuum chamber is divided into a main chamber and a separate deposition chamber connected by a narrow aperture. The organic precursor evaporation is confined to the deposition chamber, segmenting the vapor generation space from the main chamber. This prevents the sharp partial pressure increase from affecting the entire chamber while maintaining controlled deposition on the substrate.
Solution Approach 2:
A cold trap is introduced as an intermediary component between the evaporator source and the substrate. The cold trap captures excess vapor molecules that would otherwise contribute to uncontrolled deposition on chamber surfaces. By intercepting and condensing these molecules, the cold trap mediates the vapor transport process and maintains pressure control.
2Manufacturing precision
If the evaporator source is heated to evaporate the organic precursor, then deposition occurs on the substrate, but re-evaporation from chamber surfaces makes it difficult to determine and adjust the actual deposition rate
Solution Approach 1:
By segmenting the vapor generation and deposition processes into separate chambers, the invention isolates the evaporation source from the deposition zone. This prevents re-evaporation from chamber surfaces from interfering with the measured deposition rate on the substrate, enabling accurate determination and adjustment of deposition parameters.
Solution Approach 2:
The invention implements a feedback control system where the deposition rate is continuously monitored and the evaporator heating power is adjusted accordingly. This closed-loop control compensates for variations in deposition conditions and maintains consistent, reproducible deposition rates across different runs.
3Productivity
If the inorganic precursor (halide) is used as an oxidizing agent, then the deposition process proceeds, but all chamber surfaces are coated creating a corrosive atmosphere
Solution Approach 1:
The corrosive vapor environment is confined to the deposition chamber where the inorganic precursor is introduced. The main chamber housing the evaporator and control systems remains free from corrosive contamination. This spatial segmentation protects sensitive components while maintaining deposition efficiency in the isolated deposition zone.
Solution Approach 2:
The harmful corrosive atmosphere is extracted from the main chamber by introducing the inorganic precursor only in the deposition chamber. This separates the harmful effect (corrosion) from the useful function (deposition), allowing the main chamber to remain free of corrosive materials while the deposition chamber handles the reactive precursors.
4Manufacturing precision
If conventional vapor deposition methods are used for substances with low evaporation temperatures, then deposition can be achieved, but process control is challenging and operator protection is limited
Solution Approach 1:
The deposition chamber is designed as a separate, isolated compartment for handling low-temperature evaporating materials. This segmentation contains hazardous vapors and materials within a dedicated zone equipped with appropriate safety features, protecting operators from exposure while enabling precise control of the deposition process.
Solution Approach 2:
The invention introduces automated control systems and remote handling mechanisms as intermediaries between the operator and the hazardous deposition environment. These intermediaries enable precise process control without requiring operators to be in direct contact with low-temperature evaporating materials, thereby ensuring operator safety while maintaining manufacturing precision.
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 process control, reduces re-evaporation, and improves safety by creating a corrosive-resistant environment, enabling more accurate and reproducible deposition of perovskite layers and other inorganic/organic mixed layers under high vacuum conditions.
Implementation Method 1
an evaporator unit configured to convert material into a vapor phase
Implementation Method 2
the inner chamber is configured to maintain a temperature, particularly that of the inner chamber walls and the vapor section bounded by the walls, of 25 °C or less
Implementation Method 3
reactive vapor deposition on a substrate under vacuum
Data Source
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AI summary
The invention relates to a coating apparatus (100), which is configured for reactive vapor phase deposition on a substrate under vacuum, in particular for forming perowskite layers, which comprises an evacuable vacuum chamber (10), an evaporation device (20) which is configured to produce evaporation material in the vapor phase, and a substrate holder (30) which is configured to receive the substrate, wherein in the vacuum chamber (10) there is arranged a temperature-controllable inner chamber (14), which surrounds a vapor section (41) between the evaporator device (20) and the substrate holder (30) and is configured to set an inner chamber temperature equal to or less than 25° C. The evaporation device (20) preferably has at least one heat exchanger evaporator source (50), which is connected via a temperature control medium circuit (70) to a temperature control medium reservoir (71). The invention also relates to methods for coating a substrate by means of the coating apparatus (100).