Homo- and heteroepitaxial growth of Sn-doped β-Ga2O3 layers by MOVPE

Abstract

Layers of β-Ga₂O₃in situ doped with Sn were grown on Al₂O₃ (0001) and native β-Ga₂O₃ (100) substrates by metal organic vapor phase epitaxy. Homoepitaxial growth of good-quality Sn-doped β-Ga₂O₃ layers with rocking curve values comparable to that of Czochralski-grown β-Ga₂O₃ substrates was attained. Sn incorporation in a wide range of concentrations (from 10¹⁷ to 10¹⁹ cm⁻³) was achieved without disturbing the crystallinity of the material grown. The interplay between deposition conditions and structural and electrical properties of the layers was studied. The Ga vacancy-related defects and the residual carbon from Ga-containing organic precursor carbon-related complexes have been revealed as acceptors compensating for intentionally introduced Sn donors. The advantage of employment of the melt-grown β-Ga₂O₃ crystals as homo-substrates for deposition of good-quality β-Ga₂O₃ layers is demonstrated. For the first time, n-type homoepitaxial semiconducting β-Ga₂O₃ layers were attained by MOVPE. The good quality of the epilayers was elucidated through HR-XRD measurements and a FWHM of the rocking curve of the (100) peak of 43 arcsec was obtained, which was comparable to those of the Czochralski-grown β-Ga₂O₃ substrates, demonstrating similar dislocation densities for epilayers and substrates.