Using Inherent Substrate-Dependent Nucleation to Promote Metal and Metal Oxide Selective-Area Atomic Layer Deposition

We report studies of thin film metal and metal oxide nucleation during ALD to promote native substrate bias and improve selectivity. Tungsten ALD using WF6/SiH4 onto SiO2 proceeds when surface Si-H begins to form, allowing WF6 reduction to W and elimination of SiF4. In-situ analysis indicates that initial nucleation reactions can be impeded on SiO2 by introducing reactants that help passivate active surface sites. Moreover, eliminating water during TiO2 ALD slows metal substrate oxidation to promote nucleation delay.