Single domain InxGa(1-x)P (x=0.4) films were successfully grown on Si(001) misoriented substrates by molecular beam epitaxy with solid phosphorous source. The effects of the initial 100 nm thick interfacial buffer layer such as InGaP (i.e. direct growth without buffer layer), GaP, AJP, and GaAs were examined. Superior surface morphologies were indicated for the films with GaP, A1P, and GaAs buffer layers compared with the films on InGaP buffer layer. The results indicated the necessity of some kind of initial buffer layer different from the film.