MOVPE studies of zincblende GaN on 3C-SiC/Si(0 0 1)

Wade, T.J., Gundimeda, A., Kappers, M.J., Frentrup, M., Fairclough, S.M., Wallis, D.J. ORCID: https://orcid.org/0000-0002-0475-7583 and Oliver, R.A. 2023. MOVPE studies of zincblende GaN on 3C-SiC/Si(0 0 1). Journal of Crystal Growth 611 , 127182. 10.1016/j.jcrysgro.2023.127182

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Abstract

Cubic zincblende GaN films were grown by metalorganic vapour-phase epitaxy on 3C-SiC/Si (0 0 1) templates and characterized using Nomarski optical microscopy, atomic force microscopy, X-ray diffraction, and transmission-electron microscopy. In particular, structural properties were investigated of films where the growth temperature of a GaN epilayer varied in the range of 830 °C to 910 °C and the gas-phase V/III-ratio varied from 15 to 1200 at a constant reactor pressure of 300 Torr. It was observed that with increasing epi temperature at a constant V/III-ratio of 76, the film surface consisted of micrometer-sized elongated features aligned along [1 –1 0] up to a temperature of 880 °C. The zincblende phase purity of such samples was generally high with a wurtzite fraction of less than 1%. When grown above 880 °C the GaN surface morphology degraded and the zincblende phase purity reduced as a result of inclusions with the wurtzite phase. A progressive narrowing of the 002 reflection with increasing epi growth temperature suggested an improvement of the film mosaicity. With increasing V/III-ratio at a constant growth temperature of 880 °C, the film surface formed elongated features aligned along [1 –1 0] at V/III values between 38 and 300 but the morphology became granular at both lower and higher V/III values. The zincblende phase purity is high at V/III values below 300. A slight broadening of the 002 X-ray diffraction reflection with increasing V/III-ratio indicated a small degradation of mosaicity. Scanning electron diffraction analyses of cross-sectional transmission-electron micrographs taken of a selection of samples illustrated the spatial distribution, quantity and structure of wurtzite inclusions within the zincblende GaN matrix. Within the limits of this study, the optimum epilayer growth conditions at a constant pressure of 300 Torr were identified to be at a temperature around 860 °C to 880 °C and a V/III-ratio in the range of 23 to 76, resulting in relatively smooth, zincblende GaN films without significant wurtzite contamination.

Item Type:	Article
Date Type:	Publication
Status:	Published
Schools:	Engineering
Publisher:	Elsevier
ISSN:	0022-0248
Date of First Compliant Deposit:	14 April 2023
Date of Acceptance:	14 March 2023
Last Modified:	08 May 2023 19:53
URI:	https://orca.cardiff.ac.uk/id/eprint/158842

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