Structural characteristics of epitaxial SnO2 films deposited on a- and m-cut sapphire by ALD

Epitaxial SnO2 thin films were grown on (1 1 0) (a-cut) and (1 0 0) (m-cut) sapphire substrates using plasma enhanced atomic layer deposition (PEALD) with dibutyltindiacetate (DBTDA) as a precursor. X-ray diffraction, X-ray pole figure, and high resolution TEM analyses revealed that SnO2 film deposited on a-cut sapphire was (1 0 1) oriented with a small component of (2 0 0) orientation, and the (1 0 1) planes were slightly tilted due to the presence of (2 0 0) plane and/or twinning. SnO2 film on m-cut sapphire was strongly (0 0 1) oriented with a small amount of the (3 0 1) orientation. The determined in-plane orientation relationships were [0 1 0]SnO2//[0 0 1]Al2O3 and [1 0 1̄]SnO2//[1̄ 1 0]Al2O3 (a-cut) and [0 1 0]SnO2//[0 0 1̄]Al2O3 and [1 0 0]SnO2//[0 1 0]Al2O3 (m-cut) consistent with the previous reports.