Published online by Cambridge University Press: 15 February 2011
The initial growth of polycrystalline silicon (Si) and germanium-silicon alloys (GexSi1−x) from SiH4 and GeH4, where x is in the range of 0-0.4, in an RTMP reactor has been investigated using an in situ monitoring technique called reflectometry. An inhibition time is found which, for poly-Si in the temperature range of 550–650°C decreases with increasing temperature and for poly-GexSi1−x in the temperature range of 500–625°C shows the same behavior. The effect of total pressure, ranging from 0.10–1.20 mbar, is even stronger: an increasing pressure sharply decreases the inhibition time. For a selective deposition a low SiH4 and GeH4 partial pressure seems favorable, while for a non-selective deposition of poly-GexSi1−x alloys on (gate) oxides (for Thin Film Transistor applications) a high pressure or a pressure pulse at the start of the deposition process can be used.