Handbook of Silicon Based MEMS Materials and Technologies

26.5. ALD Reactors

26.5.1. Process Requirements, Reactor Types

The basic requirement of an ALD reactor is to create conditions for the ALD process, to supply necessary reactants at the required reaction temperature, one at a time, into interaction with the substrate surface. A reaction cycle in an ALD process consists of at least two different reaction sequences separated by purge sequences. For high-quality ALD material a key property of a reactor is its ability for a strict separation of the process sequences. The reactor alone cannot guarantee qualified ALD material—the chemistry of the processes is exceedingly important, as well as proper handling of the chemicals. Favorable ALD chemistry assumes highly reactive reactants, resulting in a ...