Single-crystal hexagonal perovskite YAlO3 epitaxially on GaAs(111)A and (001) using atomic layer deposition

• Published in: Microelectronic engineering Vol. 178; pp. 125 - 127
• Main Authors: Cheng, C.K., Young, L.B., Lin, K.Y., Lin, Y.H., Wan, H.W., Lu, G.J., Chang, M.T., Cai, R.F., Lo, S.C., Li, M.Y., Hsu, C.H., Kwo, J., Hong, M.
• Format: Journal Article
• Language: English
• Published: Amsterdam Elsevier B.V 25.06.2017; Elsevier BV
• Subjects: Aluminum oxide; Ambience; Annealing; Atomic layer deposition; Atomic layer epitaxy; Epitaxial growth; Gallium arsenide; Hexagonal; Multilayers; Perovskite; Perovskite single crystal films; Single crystals; Sub-nano-laminated structure; Substrates; Thin films; Yttrium oxide; Perovskite single crystal films; Atomic layer deposition; Hexagonal; Sub-nano-laminated structure
• ISSN: 0167-9317; 1873-5568
• DOI: 10.1016/j.mee.2017.04.048

Hexagonal perovskite YAlO3 films were epitaxially grown on both GaAs(001) and GaAs(111)A substrates by utilizing sub-nano-laminated ALD-Y2O3/Al2O3 multilayers with a post-deposition rapid thermal annealing (RTA) to 900°C in He ambience. The c-axis of the YAlO3 films was aligned along the surface normal of GaAs(001) and GaAs(111)A substrates. Excellent crystallinity was evidenced by the pronounced thickness fringes and the narrow peak width of YAlO3(0004) θ-rocking scan ~0.026°, which is close to that of GaAs substrate peak ~0.01°, suggesting a high quality epitaxy despite a large lattice mismatch >6% between the substrates and the films. YAlO3 was found to be single domain as grown on GaAs(111)A but has two rotational domains on GaAs(001). The interfaces between YAlO3 and both GaAs(111)A and GaAs(001) remained atomically abrupt after 900°C RTA. [Display omitted] •Forming hexagonal YAlO3(YAP) via 900oC RTA sub-nano-laminated Y2O3/Al2O3 on GaAs.•Epitaxial growth of ALD-YAP on GaAs(001) and (111)A despite a >6% mismatch.•Excellent crystallinity of YAlO3 with narrow θ-rocking scan ~ 0.026o FWHM and clear thickness fringes.•Epitaxial YAP(0001) along substrate surface normal•YAP having in-plane single- and two-domain on GaAs(111)A and GaAs(001).