A synchrotron radiation photon spectroscopic study was made of chemical bonding at the interface between these materials. Thin Si films were deposited, at 450 or 500C, onto various GaAs substrates. These included As-rich GaAs (100) and GaAs (111)B surfaces, as well as Ga-rich GaAs (100) and GaAs (111)A surfaces. A comparison was made of the properties of these interfaces. In the case of As-rich GaAs, the Si bonded only to As. No Ga-Si bonds were formed. The Si atoms occupied the equivalent of next-layer Ga sites. Neither As nor Ga segregation to the surface of the Si film was observed. In the case of the Ga-rich GaAs (100)-(4 x 2) and GaAs (111)A surfaces, Ga-Si bonds formed at the interface. The As segregated to the surface of the Si film, leaving As vacancies at the interface. The behavior of the GaAs (111)B surface was more complicated.

S.Heun, M.Sugiyama, S.Maeyama, Y.Watanabe, K.Wada, M.Oshima: Physical Review B, 1996, 53[20], 13534-41