ALD

ALD (Atomic Layer Deposition) is a technique for forming compound thin films by chemically adsorbing constituent atoms or molecules layer by layer, although due to the size of the adsorbing molecules and resulting steric hindrance, it is not strictly adsorption by individual layers.

The film thickness increases proportionally with the number of cycles of the molecular formation cycle of chemisorption and modification reactions. While the deposition rate is slow, a key feature of ALD is its ability to form films with uniform thickness over any surface shape and to control thin film thickness at the nanometer level.