Formation of SiGe alloys using ion beam mixing followed by ion beam induced epitaxial crystallization

SiGe was epitaxially grown on Si substrates by means of ion beam mixing of Ge into Si followed by ion beam induced epitaxial crystallization. Ge layers were deposited on Si(1 0 0) substrates to a thickness of 180 nm by radio frequency sputtering. Ge ions with 400 keV were irradiated towards the Ge/Si interface for ion beam mixing with various doses (6.0 × 10 16, 1.0 × 10 17 and 1.5 × 10 17 cm −2) at room temperature. Rutherford backscattering spectroscopy measurement revealed that amorphous SiGe buffer layers were formed with gradual increase of Ge composition from Si substrates to Ge layers with the aid of Ge sputtering during mixing. The amorphous SiGe buffer layers were crystallized epitaxially from Si substrates by 2.0 MeV Ge ion irradiation to a dose of 1.0 × 10 16 cm −2 at a substrate temperature of 350 °C.