Determination of atomic-scale chemical composition at semiconductor heteroepitaxial interfaces by high-resolution transmission electron microscopy. (March 2018)

• Record Type: Journal Article
• Authors: Wen, C.; Ma, Y.J.
• Is Part Of: Micron. Volume 106(2018)
• Page Start: 48
• Page End: 58
• Publication Date: 2018-03
• Subjects: 81.70.Jb -- 68.35.bg -- 68.37.Og -- 42.30.−d; Atomic-scale chemical composition -- Heteroepitaxial interface -- AlN/6H-SiC -- AlSb/GaAs -- High-resolution transmission electron microscopy -- Image deconvolution; Microscopy -- Periodicals; Electron Probe Microanalysis -- Periodicals; Microscopy -- Periodicals; Microscopie -- Périodiques; Microscopy; Periodicals; 502.82
• DOI: 10.1016/j.micron.2018.01.003
• Languages: English
• ISSNs: 0968-4328

Abstract

Highlights: AlN/6 H -SiC and AlSb/GaAs heteroepitaxial interfaces were studied by quantitative HRTEM. Several series of conventional 300-kV field-emission-gun HRTEM images were simulated. The structure images with ∼1 Å resolution were restored by deconvolution processing. Variations in compositions were determined for the atomic intermixing and Lomer dislocation. The effect of dynamical scattering on image contrast analysis was also evaluated. Abstract: The determination of atomic structures and further quantitative information such as chemical compositions at atomic scale for semiconductor defects or heteroepitaxial interfaces can provide direct evidence to understand their formation, modification, and/or effects on the properties of semiconductor films. The commonly used method, high-resolution transmission electron microscopy (HRTEM), suffers from difficulty in acquiring images that correctly show the crystal structure at atomic resolution, because of the limitation in microscope resolution or deviation from the Scherzer-defocus conditions. In this study, an image processing method, image deconvolution, was used to achieve atomic-resolution (∼1.0 Å) structure images of small lattice-mismatch (∼1.0%) AlN/6 H -SiC (0001) and large lattice-mismatch (∼8.5%) AlSb/GaAs (001) heteroepitaxial interfaces using simulated HRTEM images of a conventional 300-kV field-emission-gun transmission electron microscope under non-Scherzer-defocus conditions. Then, atomic-scale chemical compositions at the interface were determined for the atomic intermixing and Lomer dislocation with an atomic step by analyzing the deconvoluted image contrast. Furthermore, the effect of dynamical scattering on contrast analysis was also evaluated for differently weighted atomic columns in the compositions.