MULTILAYER ALD COATING FOR CRITICAL COMPONENTS IN PROCESS CHAMBER

A method includes: forming a first coating comprising amorphous rare earth metal-containing oxide directly on a surface of an article using a first atomic layer deposition (ALD) process that includes repeating a process of alumina deposition cycles followed by rare earth metal oxide deposition cycles N1 times, the first coating characterized by a first thickness; forming a second coating comprising crystalline rare earth metal oxide on the first coating using a second ALD process, the second coating characterized by a second thickness; forming a third coating comprising amorphous rare earth metal-containing oxide on the second coating using a third ALD process that includes repeating a process of alumina deposition cycles followed by rare earth metal oxide deposition cycles N2 times, the third coating characterized by a third thickness; and forming a fourth coating comprising crystalline rare earth metal oxide on the third coating using a fourth ALD process.