In Situ Control Of Si(100) And Ge(100) Surface Preparation For The Heteroepitaxy Of III-V Solar Cell Architectures

Si(100) and Ge(100) substrates essential for subsequent III-V integration were studied in the hydrogen ambient of a metalorganic vapor phase epitaxy reactor. Reflectance anisotropy spectroscopy (RAS) enabled us to distinguished characteristic configurations of vicinal Si(100) in situ: covered with oxide, cleaned by thermal removing in H-2, and terminated with monohydrides when cooling in H-2 ambient. RAS measurements during cooling in H-2 ambient after the oxide removal process revealed a transition from the clean to the monohydride terminated Si(100) surface dependent on process temperature. For vicinal Ge(100) we observed a characteristic RA spectrum after annealing and cooling in H-2 ambient. According to results from X-ray photo electron spectroscopy and Fourier-tranform infrared spectroscopy the spectrum corresponds to the monohydride terminated Ge(100) surface.