KINETICS OF SI(111) SURFACE ETCHING BY A SELENIUM MOLECULAR BEAM
S.A. Ponomarev1,2, D.I. Rogilo1, A.S. Petrov1, D.V. Shcheglov1, A.V. Latyshev1
1Rzhanov Institute of Semiconductor Physics, Siberian Branch, Russian Academy of Sciences, Novosibirsk, Russia
2Novosibirsk State University, Novosibirsk, Russia
Keywords: кремний, селен, травление, сублимация, поверхность, отражательная электронная микроскопия, silicon, selenium, etching, sublimation, surface, reflection electron microscopy
Abstract
Three modes of the kinetics of the Si(111) surface etching by a selenium molecular beam have been distinguished by in situ ultrahigh vacuum reflection electron microscopy. At low temperatures (≲650 °C, depending on the Se deposition rate), the etching kinetics is limited by the energy of SiSe2 molecule formation and desorption, and the surface is completely covered with an impurity-induced “1×1”-Se phase of silicon selenide. In the temperature range of ~700-1100 °C, the etching rate is limited by the deposited Se flux and does not depend on the temperature, surface structure, and etching mechanism (step flow or periodic 2D island nucleation). At high temperatures (≳1150 °C), sublimation of Si atoms starts to make the major contribution to the silicon flux from the surface. We have formulated a theoretical model that describes the temperatures and the kinetics of the transitions between the etching modes.
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