Sustained Area-Selectivity in Atomic Layer Deposition of Ir Films: Utilization of Dual Effects of O 3 in Deposition and Etching

• Published in: Small (Weinheim an der Bergstrasse, Germany) Vol. 20; no. 46; p. e2402543
• Main Authors: Kim, Han, Kim, Taeseok, Chung, Hong Keun, Jeon, Jihoon, Kim, Sung-Chul, Won, Sung Ok, Harada, Ryosuke, Tsugawa, Tomohiro, Kim, Sangtae, Kim, Seong Keun
• Format: Journal Article
• Language: English
• Published: Germany 01-11-2024
• Subjects: iridium; area‐selective deposition; atomic layer deposition; etching; ozone
• ISSN: 1613-6810; 1613-6829
• DOI: 10.1002/smll.202402543

Area-selective deposition (ASD) based on self-aligned technology has emerged as a promising solution for resolving misalignment issues during ultrafine patterning processes. Despite its potential, the problems of area-selectivity losing beyond a certain thickness remain critical in ASD applications. This study reports a novel approach to sustain the area-selectivity of Ir films as the thickness increases. Ir films are deposited on Al
O
as the growth area and SiO
as the non-growth area using atomic-layer-deposition with tricarbonyl-(1,2,3-η)-1,2,3-tri(tert-butyl)-cyclopropenyl-iridium and O
. O
exhibits a dual effect, facilitating both deposition and etching. In the steady-state growth regime, O
solely contributes to deposition, whereas in the initial growth stages, longer exposure to O
etches the initially formed isolated Ir nuclei through the formation of volatile IrO
. Importantly, longer O
exposure is required for the initial etching on the growth area(Al
O
) compared to the non-growth area(SiO
). By controlling the O
injection time, the area selectivity is sustained even above a thickness of 25 nm by suppressing nucleation on the non-growth area. These findings shed light on the fundamental mechanisms of ASD using O
and offer a promising avenue for advancing thin-film technologies. Furthermore, this approach holds promise for extending ASD to other metals susceptible to forming volatile species.