Laser & Optoelectronics Progress, Volume. 53, Issue 3, 31202(2016)

Study of Instrument for Measuring Oxide Layer on Surface of Silicon Sphere Used for Avogadro Project

Liu Wende*, Chen Chi, Fan Qiming, Chu Chu, and Luo Zhiyong
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    The precision measurement of Avogadro constant and realization of mass unit kg based on atom counting of single crystal silicon require the measurement of the mass and volume of a silicon sphere. The non-homogeneously distributed oxide layer, which is several nanometer thick on the surface of the sphere, is key to the correction value of the above parameters. The coordination system of the Si sphere is determined by Laue crystallography and laser marking. Different driving approaches of the Si sphere are compared. The automatic scanning instrument is set up based on spectroscopic ellipsometer. The repeatability and stability are investigated, with the scanning results of the NIM#3 Si sphere being presented. It is indicated that the short-term repeatability of the ellipsometric scanning of the surface oxide layer reaches 0.04 nm.

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    Liu Wende, Chen Chi, Fan Qiming, Chu Chu, Luo Zhiyong. Study of Instrument for Measuring Oxide Layer on Surface of Silicon Sphere Used for Avogadro Project[J]. Laser & Optoelectronics Progress, 2016, 53(3): 31202

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    Paper Information

    Category: Instrumentation, Measurement and Metrology

    Received: Sep. 8, 2015

    Accepted: --

    Published Online: Jan. 22, 2016

    The Author Email: Wende Liu (wendeliu@nim.ac.cn)

    DOI:10.3788/lop53.031202

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