GROWTH OF EPITAXIAL SIGE NANOSTRUCTURES AT LOW-TEMPERATURE ON SI(100)USING HOT-WIRE ASSISTED GAS-SOURCE MOLECULAR-BEAM EPITAXY

Ge/Si and Si1-xGex nanostructures were grown on Si(100) at 350 degrees C substrate temperature with a significant growth rate of about 10 An gstrom min(-1) using hot-wire decomposition of disilane and germane in an ultrahigh vacuum environment, A quartz crystal microbalance (QCM) was used to monitor growth rates and to study the influence of feed ga s pressures. In-situ X-ray photoelectron spectroscopy measurements all owed us to calibrate alloy stoichiometry monitored by QCM. Ex-situ hig h-resolution transmission electron microscopy observations demonstrate d the 2D epitaxial growth of partly relaxed nanolayers. These promisin g results may be closely related to a surfactant-like role of atomic h ydrogen, which appears as a beneficial sub-product of the hot-wire dec omposition process of hydride sources. (C) 1997 Elsevier Science S.A.