Selective Deposition of Platinum by Atomic Layer Deposition Using Terraced Oxide Surfaces

Atomic layer deposition (ALD) is widely used in science and technology, particularly in microelectronics, because it allows well-controlled production of highly conformal thin films. Technoindustrial advancements in microelectronics require more accurate guidance of deposition, as features in electronic devices keep shrinking. Therefore, improved lithographic capabilities are needed, and bottom-up, self-aligned methods of lithography have attracted much attention. In this context, step decoration has been extensively explored for some decades, but ALD was seldom, if ever, considered. Gaining a better fundamental understanding of such processes is an important milestone toward their practical implementation. Here, using trimethyl(methylcyclopentadienyl)platinum(IV), MeCpPtMe₃, and O₃ on terraced α-Al₂O₃ (sapphire) miscut surfaces, we demonstrate selective deposition of platinum particles deposited by ALD. An observed interconnection between the selectivity and the miscut angle of the surface was discussed and modeled. These results shed light on the role of low-coordination surface-sites on terraced surfaces in the guidance of deposition performed by ALD.