Surface free energy modification of CaF by atomic-height island 2 formation on heteroepitaxy of GaAs on CaF2

An epitaxial GaAs film with a flat surface was grown on a CaF2 film by means of surface free energy modification of CaF2 by atomic-height island formation. An additional low-temperature deposition at a final stage of growth of the CaF2 film on Si 111. produced high density islands whose height was one monolayer of CaF2 on the terraces. This surface structure contributed to enhance wettability of overgrown GaAs. As a result, 1.3-mm-thick GaAs film on CaF2rSi 111.in which rms of surface roughness was 8 nm and electron mobility was 2000 cm2rVs in the Si doped layer 2=1017 cmy3. was obtained in this method. q1998 Elsevier Science B.V. All rights reserved.