High-Throughput Area-selective Spatial Atomic Layer Deposition of SiO 2 with Interleaved Small Molecule Inhibitors and Integrated Back-Etch Correction for Low Defectivity.

A first-of-its-kind area-selective deposition process for SiO 2  is developed consisting of film deposition with interleaved exposures to small molecule inhibitors (SMIs) and back-etch correction steps, within the same spatial atomic layer deposition (ALD) tool. The synergy of these aspects results in selective SiO 2  deposition up to ∼23 nm with high selectivity and throughput, with SiO 2  growth area and ZnO non-growth area. The selectivity is corroborated by both X-ray photoelectron spectroscopy (XPS) and low-energy ion scattering spectroscopy (LEIS). The selectivity conferred by two different SMIs, ethylbutyric acid and pivalic acid, has been compared experimentally and theoretically. Density functional theory (DFT) calculations reveal that selective surface functionalization using both SMIs is thermodynamically controlled, while the better selectivity achieved when using trimethylacetic acid can be explained by its higher packing density compared to ethylbutyric acid. By employing the trimethylacetic acid as SMI on other starting surfaces (Ta 2 O 5 , ZrO 2 , etc.) and probing the selectivity, we demonstrate a broader use of carboxylic acid inhibitors for different substrates. We believe that the current results highlight the subtleties in SMI properties such as size, geometry and packing, as well as interleaved back-etch steps, which are key in developing ever more effective strategies for highly-selective deposition processes. This article is protected by copyright. All rights reserved.