In situ three-dimensional X-ray reciprocal-space mapping of GaAs epitaxial films on Si(001)

Takahashi, Masamitsu; Nakata, Yuka*; Suzuki, Hidetoshi*; Ikeda, Kazuma*; Kozu, Miwa; Hu, W.; Oshita, Yoshio*

Epitaxial growth of III-V semiconductors on silicon substrates is a longstanding issue in semiconductor technology including optoelectronics, high-mobility devices and solar cells. In addition to a lattice mismatch of 4%, formation of antiphase domain boundaries makes the growth of GaAs/Si(001) more complicated than that of congeneric combinations, such as Ge/Si(001) and InGaAs/GaAs(001). In the present study, defects in GaAs/Si(001) epitaxial films are investigated by three-dimensional X-ray reciprocal-space mapping technique, which we have successfully applied for InGaAs/GaAs(001) growth. Experiments were carried out at a synchrotron beamline 11XU at SPring-8 using a molecular-beam epitaxy chamber integrated with a multi-axis X-ray diffractometer. Streaky scattering extending from the GaAs 022 peak in the directions was observed, indicating development of plane defects, such as facets and stacking faults.