Area-selective atomic layer deposition of palladium

Abstract

We report area-selective deposition of palladium using sequential area-blocking and area-activation ALD processes. Thermal atomic layer deposition (ALD) of palladium is investigated at 100 °C using palladium (II) hexafluoroacetylacetonate and hydrogen. Palladium deposition does not proceed at such a low temperature unless catalytic sites are present to dissociate hydrogen during Pd film nucleation and before sufficient Pd has accumulated to serve as the catalyst for hydrogen dissociation. Ultrathin (<2 nm) nickel metal surfaces served as the initial catalytic sites and are prepared via low temperature (100 °C) reduction of NiO ALD films using a H-atom doser operating at 3 × 10−5 Torr. The Ni0 films are shown to seed the ALD of Pd, demonstrating a route to Pd ALD by area activation. Blanket NiO films are used to study Pd ALD growth and patterned NiO films, formed by area-blocking ALD, are used to demonstrate a bottom-up approach to patterned Pd films.