Cyclic Metal Halide Deposition for Uniform Low-Temperature Thin Films
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Solution Overview
Problem
The production of uniform metal halide thin films, such as cesium iodide (CsI), is challenging in large-scale applications, limiting their use in fields like imaging detectors and solar cells.
Innovation Solution
A cyclic deposition process involving vapor-phase metal and halogen precursors is used to form metal halide-comprising materials on a substrate, with the metal precursor having an oxidation state of +1 bonded to an organic ligand, allowing for the formation of binary and ternary metal halides at low temperatures.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If conventional deposition methods are used to produce metal halide thin films, then the production process can be performed, but uniform film formation in large scale remains difficult
Solution Approach 1:
The deposition process is divided into multiple sequential cycles, with each cycle depositing a controlled thickness of film. The method uses repeated pulsing of metal precursor and halogen precursor to build up uniform film layer by layer, enabling precise control over film uniformity while scaling to large substrates
Solution Approach 2:
The invention employs periodic pulsing of metal precursor and halogen precursor into the reaction chamber. Each precursor is introduced in controlled pulses with purging steps in between, creating a cyclic deposition process that ensures uniform film formation across large-scale substrates while maintaining precise thickness control
2Manufacturing precision
If high temperature deposition is used to form metal halide films, then film formation can be achieved, but substrate damage and process complexity increase
Solution Approach 1:
The invention changes the deposition temperature parameter from conventional high temperatures to low temperatures (below 150°C). This is achieved by using organometallic precursors that decompose and react at low temperatures, forming high-quality metal halide films without substrate damage or excessive thermal stress
Solution Approach 2:
The invention replaces thermal energy-driven deposition with chemically-driven deposition using organometallic precursors. The chemical reactions of the precursors with halogen sources form metal halide films at low temperatures, substituting the need for high thermal energy while maintaining film formation quality
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 method enables the deposition of uniform metal halide films with controlled thickness and composition, suitable for various semiconductor applications, including perovskite solar cells and imaging detectors.
Implementation Method 1
A cyclic method of depositing a metal halide-comprising material on a substrate by a cyclic deposition process is disclosed. The method comprises providing a substrate in a reaction chamber, providing a metal precursor into the reaction chamber in a vapor phase and providing a halogen precursor into the reaction chamber in a vapor phase to form the metal halide-comprising material on the substrate
Implementation Method 2
providing a metal precursor into the reaction chamber in a vapor phase and providing a halogen precursor into the reaction chamber in a vapor phase to form the metal halide-comprising material on the substrate
Data Source
AI summary
The current disclosure relates to a method of depositing a metal halide-comprising material on a substrate by a cyclic deposition process. The method comprises providing a substrate in a reaction chamber, providing a metal precursor into the reaction chamber in a vapor phase and providing a halogen precursor into the reaction chamber in a vapor phase to form the metal halide-comprising material on the substrate. In the method, the metal precursor comprises a metal atom having an oxidation state of +1 bonded to an organic ligand. Also, a deposition assembly for depositing a metal halide-comprising material is disclosed.