Germanium (Ge) dots were formed on Si(001)(-2) x 1 surface by gas-source NME using germane (GeH4) and monomethylsilane (MMS). Predeposition of C atoms using MMS in prior to Ge growth greatly reduced the size and increased the density of the Ge dots grown on the surface. Carbon atoms were introduced via saturated adsorption of MMS followed by annealing to remove the adsorbed hydrogen atoms. To clarify the behavior of H and C atoms during annealing, we investigated the surface Si hydrides using multiple-internal-reflection Fourier transform infrared spectrometry. After an annealing at 500 degrees C for 1 min, almost all surface hydrogen atoms were desorbed and almost all C atoms were diffused into the subsurface and the bulk of the Si substrate, which is related to the observed miniaturization of the Ge dots and the increase of their density as well. (c) 2005 Elsevier B.V. All rights reserved.