Real-time optical characterization of heteroepitaxy by organometallic chemical vapor deposition

Heteroepitaxy of GaP on Si(100) and GaAs(100) is investigated under organom etallic chemical vapor deposition conditions using combined spectroscopic e llipsometry (SE) and non-normal-incidence reflectance-difference (-anisotro py) spectroscopy. Real-time monitoring greatly assists in identifying optim um starting surfaces for heteroepitaxy since prolonged exposure to PH3 resu lts in roughening of Si(100) and GaAs(100) surfaces, in agreement with prev ious work. Real-time SE data of GaP on Si indicate that under our condition s GaP and Si interpenetrate as optically identifiable materials over the fi rst 75 Angstrom, suggesting that either trimethylgallium or a reaction by-p roduct can act as a catalyst for the formation of Si(lll) facets. (C) 2000 American Vacuum Society. [S0734-2101(00)16104-4].