Kinetics of Ge growth at low temperature on Si(001) by ultrahigh vacuum chemical vapor deposition

Abstract

The growth of germanium at low temperature by ultrahigh vacuum chemical vapor deposition on Si(001) is investigated in real time by reflection high-energy electron diffraction. These observations are complementarily checked by atomic force microscopy, Rutherford backscattering spectrometry, transmission electron microscopy, and x-ray diffraction experiments. It can be seen that the currently observed Stranski–Krastanov-related two-dimensional (2D) to three-dimensional transition is avoided at 330 °C and that the major part of the relaxation process occurs during the deposition of the first two monolayers. Then, the measured in-plane lattice parameter evolves slowly and approaches that of bulk Ge after deposition of 50 monolayers. The corresponding relaxation equals 83%. The resulting surface is flat, with a rms roughness of 0.55 nm. The relaxation is found to be mainly due to misfits dislocations located at the Ge/Si interface. Regrowth experiments at 600 °C show that the low-temperature films are not stable for thicknesses below 27 nm. In spite of the nearly complete relaxation observed for 7.5 nm, a much higher thickness is needed to enable a continuous 2D growth at 600 °C. Finally, a 500-nm-thick film, obtained with a low-temperature Ge buffer and with a Ge regrowth at high temperature, exhibits a channeling-to-random Rutherford backscattering spectrometry ratio (min) of 4%, which indicates a good crystalline quality. ©2005 American Institute of Physic

Epitaxial growth and thermal stability of Ge1−xSnx alloys on Ge-buffered Si(001) substrates

“…High-quality Ge thin films have been successfully grown on Si by a two-step UHV/CVD growth technique [16,17]. In this study, the two-step growth method was applied to grow Ge thin film by MBE instead of UHV/CVD.…”

The influence of low-temperature Ge seed layer on growth of high-quality Ge epilayer on Si(100) by ultrahigh vacuum chemical vapor deposition

“…[10,13,14,18]). It is suggested that it is very difficult to fully relieve the strain in the Ge seed layer when growing at LT (300-400 1C).…”

“…1(c)). The temperature of 350 1C is not low enough to prohibit three-dimensional growth [18], and the surface becomes much rough. However, after deposition of HT Ge layer, the surface becomes smooth and 2 Â 1 reconstruction is rebuilt ( Fig.…”

Specific features of formation and propagation of 60° and 90° misfit dislocations in GexSi1−x/Si films with x>0.4

“…The amount of defects in such heterostructures was reduced by growing Ge or close to Ge layers of GeSi at low temperatures with subsequent cycles of annealing [1,2]. Surface-active impurities (surfactants) were used to make the growing film surface planar [3][4][5][6][7].…”