PRECISION MEASUREMENTS OF INTERATOMIC DISTANCES IN A SILICON CRYSTALLINE LATTICE BY AN OPTICAL METHOD USING A SCANNING INTERFEROMETER
E.V. Sysoev1, A.V. Latyshev2
1Technological Design Institute of Scientific Instrument Engineering, Siberian Branch, Russian Academy of Sciences, Novosibirsk, Russia
2Rzhanov Institute of Semiconductor Physics, Siberian Branch, Russian Academy of Sciences, Novosibirsk, Russia
Keywords: scanning longitudinal shear interferometer, atomically smooth surface, Linnik interferometer, interference measurements, interatomic distance, echelon of atomic steps
Abstract
The influence of the interferometer optical system characteristics on the distribution of spectral power density of partially coherent light passing through the system is investigated. The results of effective wavelength measurements for partially coherent light sources are presented. It is shown that the optical system transforms the spectra, which leads to a systematic error of interference measurements using the scattered light phase. With atomically smooth surfaces used as a reference mirror, the influence of this system on the phase distortion is investigated. The systematic error is found to be approximately 5 nm in terms of height owing to phase distortion. It is shown that the use of atomically smooth surfaces as a perfect measurement surface allows this error to be significantly reduced down to 0.12 nm. The results of measuring an echelon of atomic steps with a countable number of monoatomic layers on the silicon crystal surface are reported. The interatomic (interplane) distance in the crystal lattice of Si with orientation [111] is experimentally measured for the first time by low-coherence optical interferometry, and its value is found to be 3.145 0.003Å.
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