A technique has been developed for frequency analysis of the IR reflection spectrum to determine the thickness and order of the layers in the epitaxial structure of silicon carbide. Calculations for the 4H-SiC epitaxial structure have been performed. The method has been shown to be highly sensitive to optical boundaries resulting from a sequential increase in the doping level during the layer growth. Keywords: Silicon carbide, epitaxial layer, IR reflection, spectrum

The possibility to increase the responsivity of 4H-SiC p+– n –n+ - photodiodes by varying the thickness of the p+ - epilayer has been studied. It is shown that the thinning of the upper epilayer by RIE with the use of metal contacts as a mask makes it possible to control both the maximum responsivity and the spectral dependence of the responsivity of photodiodes and does not lead to degradation of dark electrical characteristics.

Разработана методика частотного анализа ИК спектра отражения для определения толщин и порядка расположения слоев в эпитаксиальной структуре (ЭС) карбида кремния, выполнены расчеты для 4H-SiC ЭС, показана высокая чувствительность метода к оптическим границам, возникшим в результате последовательного увеличения уровня легирования в процессе роста слоя.

Abstract Silicon carbide substrates and epitaxial structures are investigated by nondestructive contactless methods. Parameters of the disrupted surface layer and roughnesses are determined using ellipsometry and atomic force microscopy. The free charge carrier concentration is determined by IR spectroscopy. The thicknesses in the multilayer epitaxial structure on SiC are determined using IR spectroscopy and scanning electron microscopy.