Area-Selective Atomic Layer Deposition of Noble Metals: Polymerized Fluorocarbon Layers as Effective Growth Inhibitors
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Selective deposition is a powerful self-aligned precision materials processing strategy which can hugely benefit next-generation nanoelectronics, catalysis, and energy conversion/storage fields. Atomic layer deposition (ALD) is showing a significant promise in enabling area-selective deposition using various growth blocking layers including self-assembled monolayers (SAMs) and various polymers. However, these blocking layers are not compatible with energetic co-reactants like ozone and plasma radicals, showing relatively fast degradation and losing their growth inhibition character. In this work, we demonstrate that polymerized fluorocarbon surfaces function as effective growth inhibitors for ALD-grown Pt and Pd films. Besides effectively inhibiting film growth with considerable nucleation delays for, Pt experiments revealed that polymerized CFx layers are also ozone-compatible. To the best of our knowledge, this is the first demonstration of an AS-ALD process using ozone as co-reactant for noble metals. In our manuscript, we detail our observations of (Pt,Pd) film nucleation evolution and self-aligned deposition experiments on patterned samples. We have performed in-depth chemical and surface characterizations along the nucleation studies and self-aligned patterning experiments.