Saturation profile based conformality analysis for atomic layer deposition: Aluminum oxide in lateral high-aspect-ratio channels

Jihong Yim, Oili M.E. Ylivaara, Markku Ylilammi, Virpi Korpelainen, Eero Haimi, Emma Verkama, Mikko Utriainen, Riikka L. Puurunen*

*Corresponding author for this work

Research output: Contribution to journalArticleScientificpeer-review

27 Citations (Scopus)

Abstract

Atomic layer deposition (ALD) raises global interest through its unparalleled conformality. This work describes new microscopic lateral high-aspect-ratio (LHAR) test structures for conformality analysis of ALD. The LHAR structures are made of silicon and consist of rectangular channels supported by pillars. Extreme aspect ratios even beyond 10 000 : 1 enable investigations where the adsorption front does not penetrate to the end of the channel, thus exposing the saturation profile for detailed analysis. We use the archetypical trimethylaluminum (TMA)-water ALD process to grow alumina as a test vehicle to demonstrate the applicability, repeatability and reproducibility of the saturation profile measurement and to provide a benchmark for future saturation profile studies. Through varying the TMA reaction and purge times, we obtained new information on the surface chemistry characteristics and the chemisorption kinetics of this widely studied ALD process. New saturation profile related classifications and terminology are proposed.
Original languageEnglish
Pages (from-to)23107-23120
JournalPhysical Chemistry Chemical Physics
Volume22
Issue number40
DOIs
Publication statusPublished - 21 Oct 2020
MoE publication typeA1 Journal article-refereed

Funding

Funding for PillarHall-3 LHAR prototype fabrication at VTT was provided by the Academy of Finland via the Finnish Centre of Excellence on Atomic Layer Deposition and via Tekes (currently: Business Finland) via the PillarHall TUTL project (1125/31/2016). The work at Aalto University was supported by Puurunen’s starting grant and by the Academy of Finland (COOLCAT consortium, decision no. 329978 and ALDI consortium, decision no. 331082).

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