Heteroepitaxial growth of high quality InSb films on Si(111) substrates using a two-step growth method

We report the molecular beam epitaxial growth of InSb on Si(lll) substrates over the temperature range 190-400 degreesC. Epitaxial growth is achieved by suitably adjusting the growth rate, In/Sb flux ratio and substrate temperature. For growth temperatures up to 300 degreesC surface morphology and epitaxial quality of the film improve with temperature, whereas above 300 degreesC, increase in growth temperature causes deterioration in the epitaxial quality of the film. Hall measurements revealed that the electron mobility of the him increases with growth temperature and for the film grown at 300 degreesC it is about 2200 cm(2) V-1 s(-1) at room temperature (RT). Significant improvement in the electrical properties of the film is achieved using a two-step growth procedure, which involves a 300 Angstrom thick interface layer growth at 300 degreesC followed by growth at 400 degreesC. Electron mobility of a 1.8 mum thick two-step grown film at RT is 23000 cm(2) V-1 s(-1) (approximate to 19 000 cm(2) V-1 s(-1) at 70 K). This is the highest mobility value we came across for an InSb film grown on a Si(lll) substrate without buffer layer. Surface morphology, crystal quality and electrical properties of the grown films are discussed with respect to growth parameters.