Dissociative ionization and electron beam induced deposition of tetrakis(dimethylamino)silane, a precursor for silicon nitride deposition

Po Yuan Shih, Reza Tafrishi, Maicol Cipriani, Christian Felix Hermanns, Jens Oster, Armin Gölzhäuser, Klaus Edinger, Oddur Ingólfsson*

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

Abstract

Motivated by the use of tetrakis(dimethylamino)silane (TKDMAS) to produce silicon nitride-based deposits and its potential as a precursor for Focused Electron Beam Induced Deposition (FEBID), we have studied its reactivity towards low energy electrons in the gas phase and the composition of its deposits created by FEBID. While no negative ion formation was observed through dissociative electron attachment (DEA), significant fragmentation was observed in dissociative ionization (DI). Appearance energies (AEs) of fragments formed in DI were measured and are compared to the respective threshold energies calculated at the DFT and coupled cluster (CC) levels of theory. The average carbon and nitrogen loss per DI incident is calculated and compared to its deposit composition in FEBID. We find that hydrogen transfer reactions and new bond formations play a significant role in the DI of TKDMAS. Surprisingly, a significantly lower nitrogen content is observed in the deposits than is to be expected from the DI experiments. Furthermore, a post treatment protocol using water vapour during electron exposure was developed to remove the unwanted carbon content of FEBIDs created from TKDMAS. For comparison, these were also applied to FEBID deposits formed with tetraethyl orthosilicate (TEOS). In contrast, effective carbon removal was achieved in post treatment of TKDMAS, while his approach only marginally affected the composition of deposits made with TEOS.

Original languageEnglish
Pages (from-to)9564-9575
Number of pages12
JournalPhysical Chemistry Chemical Physics
Volume24
Issue number16
DOIs
Publication statusPublished - 30 Mar 2022

Bibliographical note

Funding Information:
This project has received funding from the European Union's Horizon 2020 research and innovation programme under the Marie Skłodowska-Curie grant agreement no. 722149. M. C. and O. I. acknowledge support from the Icelandic Centre of Research (RANNIS), grant no. 13049305(1-3). M. C. acknowledges a doctoral grant from the University of Iceland Research Fund.

Funding Information:
This project has received funding from the European Union's Horizon 2020 research and innovation programme under the Marie Skłodowska-Curie grant agreement no. 722149. M. C. and O. I. acknowledge support from the Icelandic Centre of Research (RANNIS), grant no. 13049305(1–3). M. C. acknowledges a doctoral grant from the University of Iceland Research Fund.

Publisher Copyright:
© 2022 The Royal Society of Chemistry.

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