Direct liquid injection chemical vapour deposition (DLI-CVD) is an innovative coating technique in which liquid ‘precursor solutions’ act as the starting material from which the coatings are formed. Using these precursor solutions enables coatings previously considered impossible for typical CVD processes, expanding the range of possible coatings considerably.
DLI-CVD precursors are usually much safer than halide compounds typically used in CVD. Furthermore, process conditions are generally gentler, requiring lower deposition temperatures and producing less chemically active or harmful by-products.
During the process, the precursors are injected into an evaporating chamber as micron-sized droplets, which are vaporized into a gaseous state. An inert carrier gas can be introduced to aid transportation of the precursor through the evaporating chamber into the main reactor, along with any reacting gases (such as oxygen, hydrogen etc.) to achieve the desired coating.
We use inductive high impedance injector nozzles give us precise control over the coating process by the fine tuning of injection parameters. Doing so, we can increase the complexity of these coatings systems to incorporate dopants or design multi-layered, multi-component coating systems.
ATL have so far used this CVD method to generate coatings for a variety of applications, such as in the nuclear fusion industry, CMCs for high temperature applications and carbon nanotube technology. With ongoing research in this broad field of CVD we are expanding our coating catalogue to help customers achieve the material solutions they require. If there is a coating that you wish to deposit that may have previously been impossible, DLI-CVD may be the solution.
Physical states of some commercially available CVD precursors for each element in the periodic table (gas in green, liquid in red, and solid in yellow) - picture credit to https://www.intechopen.com/books/chemical-vapor-deposition-for-nanotechnology/direct-liquid-injection-chemical-vapor-deposition