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HL: Fachverband Halbleiterphysik

HL 37: Preparation and characterization

HL 37.4: Vortrag

Dienstag, 1. April 2014, 10:15–10:30, POT 151

Characteristics of high-quality SnO₂ films deposited on sapphire by IBSD — •Martin Becker, Yinmei Lu, Benedikt Kramm, Angelika Polity, and Bruno K. Meyer — 1st Physics Institute, Justus-Liebig-University Giessen, Heinrich-Buff-Ring 16, 35392 Giessen, Germany

SnO₂ thin films were grown on (001) (c-cut), (012) (r-cut), (110) (a-cut) and (100) (m-cut) sapphire substrates using ion beam sputter deposition (IBSD) of a pure Sn metallic target at a constant gas mixture of 2.5 sccm argon and 15 sccm oxygen at 550^∘C substrate temperature. X-ray diffraction in Bragg-Brentano geometry revealed that SnO₂ film deposited on each substrate is grown with preferential orientation. The determined out-of-plane orientation relationships were SnO₂(100)//Al₂O₃(001) (c-cut), SnO₂(101)//Al₂O₃(012) (r-cut), SnO₂(101)//Al₂O₃(110) (a-cut) and SnO₂(002)//Al₂O₃(100) (m-cut). XRD rocking curves indicated close-to-epitaxial growth conditions, perceivable by very small full width at half maximum (FWHM). X-ray pole figure even announced epitaxial in-plane relationships. Energy dispersive X-ray spectroscopy (EDX), X-ray photoelectron spectroscopy (XPS) and secondary ion mass spectroscopy (SIMS) served as procedures to identify composition and stoichiometry. Morphology was studied by scanning electron microscopy (SEM) and atomic force microscopy (AFM), respectively, which reveal smooth and homogeneous surfaces. At room temperature free carrier densities (n-type) range between mid 10¹⁷ cm⁻³ to mid 10¹⁸ cm⁻³, whereas mobilities are still significantly lower than in bulk SnO₂.