Growth and in situ ellipsometric analysis of Si1-xGex alloys deposited by chemical beam epitaxy
Growth of strained Si1-xGex alloys on Si (100) by chemical beam epitaxy using silane and germane as gas precursors is reported. Selectivity on SiO2 patterned substrates, superlattices with sharp interfaces are easily achieved for x values varying between 0 and 25%. The incorporation rate of germanium and the growth kinetics are analyzed as a function of the germane gas flow and substrate temperature. The growth process is controlledin situ using a multi-wavelength ellipsometer. An accurate monitoring of the germanium content and thickness of multi-quantum well along with bulk structures can be obtained by this method. We show that a three-dimensional growth analysis is also worth consideration for structural characterization of the layer.