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Ellipsometric studies of nanocrystalline silicon films with the thicknesses less than 100 nm
Buchenko V. V. and Goloborodko A. A.

Taras Shevchenko National University of Kyiv, 64/13 Volodymyrska Street, Kyiv, 01601, Ukraine

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Abstract. .Our study deals with the structure of thin nanosilicon films having the thicknesses less than 100 nm. It is measured using multi-angular and spectral ellipsometry methods. Modelling of angular dependences of the ellipsometric parameters shows a significant dependence of both structure and composition of the nanosilicon films upon their thickness. In particular, the volume fraction of voids increases with decreasing thickness of the film. The effect of SiOx shell of the nanocrystals on the optical properties of our films can be neglected. When the thickness of the nanocrystalline layer is less than 50 nm, the compositions of this layer and the surface-roughness layer become practically identical. 

Keywords: nanocrystalline silicon, ellipsometry, polarimetry, chemical vapour deposition, effective medium

PACS: 07.60.Fs, 78.20.-e, 42.25.Gy
UDC: 535.3
Ukr. J. Phys. Opt. 17 124-131
doi: 10.3116/16091833/17/3/124/2016

Received: 09.06.2016

Анотація. Стаття присвячена вивченню структури тонких нанокремнійових плівок з товщинами, меншими 100 нм, за методами багатокутової та спектральної еліпсометрії. Моделювання кутових залежностей еліпсометричних параметрів показало істотну залежність структури і складу нанокремнійових плівок від їхньої товщини. Зокрема, зі зменшенням товщини плівки зростає об'ємна частка пустот. Доведено, що впливом нанокристалічної оболонки SiOx на оптичні властивості плівок можна знехтувати. Нарешті, за товщини нанокристалічного шару, меншої 50 нм, склад цього шару і шару поверхневої шорсткості практично однаковий.
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