Measuring Method for Optically Quantifying Anti-Phase Domains in Situ and Use of the Measuring Method

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This patent discloses an optical measurement method for in-situ quantification of anti-phase domains (APDs) during the heteroepitaxial growth of polar semiconductor films on non-polar substrates. The method leverages reflection anisotropy spectroscopy (RAS) to determine the concentration of APDs, which are key crystal defects that adversely affect semiconductor device performance. By comparing measurements between a test sample and a carefully prepared homoepitaxial reference, and applying correction algorithms for interference effects, the method enables real-time, accurate, and non-destructive monitoring of APD concentrations during fabrication.

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• Quality control during the manufacturing of semiconductor devices such as microelectronics and optoelectronics (e.g., LEDs, lasers, solar cells) that use polar epitaxial films on non-polar substrates.
• Process optimization in research and industrial settings for integrating III-V semiconductor technology with silicon-based technologies.
• Early detection and suppression of crystal defects during epitaxial layer growth, enabling feedback control in manufacturing equipment.
• Quality assessment and qualification of semiconductor substrates and interfaces, supporting material selection and process improvements.
• Integration as an in-line, rapid, and automated inspection tool within scalable industrial coating or fabrication lines.

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• Provides real-time, in-situ, and non-destructive quantification of APD concentrations, eliminating the need for slow and destructive ex-situ analyses (e.g., TEM, AFM).
• Greatly improves the accuracy of APD measurement by correcting for optical interference and systematic errors, reducing measurement error to under 1%.
• Enables immediate feedback and process adjustment, which can minimize defects and increase yield in semiconductor device production.
• Facilitates the development of advanced devices by allowing reliable use of inexpensive and widely available substrates, promoting cost savings and scalability.
• Easily integrable into existing industrial processes and adaptable to various relevant material systems (e.g., GaP/Si, GaAs/Ge, GaInP/Ge).

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Patent Abstract

In the heteroepitaxial deposition of polar semiconductor films onto non-polar substrates, the formation of anti-phase domains (APDs) leads to crystal defects, the concentration of which negatively affects the technological use of the layer systems in microelectronics and optoelectronics. An optical in situ characterization of the APD concentration during the preparation enables a controlling quality inspection. The known in situ measuring method for determining APD fractions is based on the reflection anisotropy spectroscopy for a heteroepitaxial deposition with APDs as a sample and without APDs as a reference and a comparison calculation of the two orthogonally polarized reflections measured on the sample and on the reference. In order to avoid an expensive ex situ verification of the reference and to improve the accuracy of the measuring method, the invention provides for a comparison with a homoepitaxially grown reference having the same surface reconstruction on the basis of the exact specification of preparation and measurement conditions and a correction of the interferences that occur on the basis of at least isotropic reflections at the boundary surface between the polar semiconductor film and the non-polar substrate. In the subsequent correction steps, further sources of anisotropies such as anisotropic reflections can also be corrected.