Synthesis of oxides in Si0.5Ge0.5 alloy by high dose oxygen ion implantation

Abstract A Si 0.5 Ge 0.5 alloy layer was implanted at a temperature of about 500 °C with doses of 0.6 × 10 18 , 1.2 × 10 18 and 1.8 × 10 18 O + cm −2 at an energy of 200 keV. The alloy layer was prepared by molecular beam expitaxy (MBE), with an 800 nm thick film of Si 0.5 Ge 0.5 alloy followed by a 75 nm thick top silicon layer on an n-type Si(100) ( ϱ = 5–20 Ω cm ) substrate. X-ray photoelectron spectroscopy measurements and Rutherford backscattering indicated that SiO and GeO compounds were formed during the oxygen bombardment. The sample implanted with a dose of 1.8 × 10 18 O + cm −2 was annealed at a temperature of 1000°C, which caused further growth of the SiO 2 phase with a concomitant reduction in the oxides of germanium and rejection of germanium from the synthesis layer. The different oxidation rates for silicon and germanium can be attributed to thermodynamic effects.