Determination of atomic-scale chemical composition at semiconductor heteroepitaxial interfaces by high-resolution transmission electron microscopy

作者：Wen, C.^*; Ma, Y. J.

来源：Micron, 2018, 106: 48-58.

DOI：10.1016/j.micron.2018.01.003

• Atomic-scale chemical composition
• Heteroepitaxial interface
• AIN/6H-SiC
• AlSb/GaAs
• High-resolution transmission electron microscopy
• Image deconvolution

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 (similar to 1.0 angstrom) structure images of small lattice-mismatch (similar to 1.0%) A1N/6H-SiC (0001) and large lattice-mismatch (similar to 8.5%) AISb/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.

• 出版日期2018-3
• 单位西南科技大学