A thermal atomic layer deposition (ALD) machine is a precise thin-film coating system that deposits materials one atomic layer at a time using alternating, self-limiting chemical reactions at elevated temperatures (150-350 degrees). It ensures high conformality and atomic-scale thickness control, ideal for high-aspect-ratio 3D structures and, typically, for creating oxides, nitrides, and other thin films

The key components and features are: (1) Reaction Chamber: Heated, high-vacuum chamber where the substrate (up to 6–8 inches, typically) is held. (2) Precursor Delivery System: Multiple heated gas lines with MFCs (Mass Flow Controllers) allow for introducing alternating precursors (e.g., metal-organic precursors and H2O, or O3). (3) Pulse/Purge Valves: High-speed, high-temperature valves, such as those found on the Veeco Savannah, control the precise, alternating dosage and inert gas purge cycles.

The mini benchtop thermal ALD has following unique features: (1) Throughput: These systems are "one-at-a-time." Coating a full roll of foil for a pilot line would require a Spatial ALD or Roll-to-Roll system, which are much larger than benchtop units. (2) Precursor Costs: While the amount used is tiny, specialized precursors (like those for solid-state electrolyte coatings) can be expensive. (3) Cycle Time: ALD is a slow process. Deposition of a 5-10 nm layer can take 1 to 2 hours depending on the cycle purge times.

The general working mechanism of the thermal ALD process are shown below:

References:

A. Cappella, et al., High Temperature Thermal Conductivity of Amorphous Al2O3 Thin Films Grown by Low Temperature ALD, Adv. Engineering Mater., 2013, 15, 1046-1050

S. E. Potts, et al., Room-Temperature ALD of Metal Oxide Thin Films by Energy-Enhanced ALD, Chemical Vapor Deposition, 2013, 19, 125-133.