Berlin 2012 – wissenschaftliches Programm
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O: Fachverband Oberflächenphysik
O 31: Clean surfaces II
O 31.4: Vortrag
Dienstag, 27. März 2012, 11:15–11:30, A 060
STM measurements on MOVPE-prepared germanium and silicon surfaces — •Johannes Luczak1, Peter Kleinschmidt1,4, Sebastian Brückner1,2, Henning Döscher1,2, Oliver Supplie1, Enrique Barrigón3, and Thomas Hannappel1,2,4 — 1Helmholtz-Zentrum Berlin, Institut Solare Brennstoffe und Energiespeichermaterialien, D-14109 Berlin — 2TU Ilmenau, Institut für Physik, Fachgebiet Photovoltaik, D-98693 — 3Instituto de Energía Solar, Universidad Politécnica de Madrid, E-28040 Madrid — 4CiS Forschungsinstitut für Mikrosensorik und Photovoltaik, D-99099 Erfurt
An important requirement to achieve low defect densities in the III-V epilayers deposited on group IV substrates is a suitable substrate surface preparation prior to heteroepitaxy. Generation of double layer steps on Si(100) or Ge(100) is desirable for subsequent anti-phase domain-free heteroepitaxy of III-V semiconductors. A contamination-free MOVPE-to-UHV transfer system allowed us to analyze different surfaces with various UHV based surface-sensitive techniques such as x-ray photo electron spectroscopy (XPS), low energy electron diffraction (LEED), and scanning tunneling microscopy (STM). STM measurements on Si(100) showed the formation of D_A or D_B - double-layer steps on a surface with an intermediate offcut of 2° in [011], depending on the process parameters. STM measurements on Ge(100) showed single-layer steps after homoepitaxial growth on substrates with 0.2° offcut in [011] direction, and double-layer steps after deoxidation on substrates with 6° offcut in [011].