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Research article - Peer-reviewed, 2020

In Situ Activation of an Indium(III) Triazenide Precursor for Epitaxial Growth of Indium Nitride by Atomic Layer Deposition

O'Brien, Nathan J.; Rouf, Polla; Samii, Rouzbeh; Ronnby, Karl; Buttera, Sydney C.; Hsu, Chih-Wei; Ivanov, Ivan G.; Kessler, Vadim; Ojamae, Lars; Pedersen, Henrik

Abstract

Indium nitride (InN) is characterized by its high electron mobility, making it a ground-breaking material for high frequency electronics. The difficulty of depositing high-quality crystalline InN currently impedes its broad implementation in electronic devices. Herein, we report a new highly volatile In(III) triazenide precursor and demonstrate its ability to deposit high-quality epitaxial hexagonal InN by atomic layer deposition (ALD). The new In(III) precursor, the first example of a homoleptic triazenide used in a vapor deposition process, was easily synthesized and purified by sublimation. Thermogravimetric analysis showed single step volatilization with an onset temperature of 145 degrees C and negligible residual mass. Strikingly, two temperature intervals with self-limiting growth were observed when depositing InN films. In the high-temperature interval, the precursor underwent a gas-phase thermal decomposition inside the ALD reaction chamber to produce a more reactive In(III) compound while retaining self-limiting growth behavior. Density functional theory calculations revealed a unique two-step decomposition process, which liberates three molecules of each propene and N-2 to give a smaller tricoordinated In(III) species. Stoichiometric InN films with very low levels of impurities were grown epitaxially on 4H-SiC. The InN films deposited at 325 degrees C had a sheet resistivity of 920 Omega/sq. This new triazenide precursor enables ALD of InN for semiconductor applications and provides a new family of M-N bonded precursors for future deposition processes.

Published in

Chemistry of Materials
2020, Volume: 32, number: 11, pages: 4481-4489
Publisher: AMER CHEMICAL SOC

    UKÄ Subject classification

    Materials Chemistry

    Publication Identifiers

    DOI: https://doi.org/10.1021/acs.chemmater.9b05171

    Permanent link to this page (URI)

    https://res.slu.se/id/publ/106888