Pulsed laser induced epitaxial crystallization of carbon-silicon alloys

Nonequilibrium Si_1-xC_x alloys produced by pulsed laser induced epitaxy from ion implanted Si have been studied in the concentration range from 0.35 to 3.8 at. % C. Films were formed by multiple energy ion implantation of carbon into {001} Si to produce nearly uniform composition profiles, followed by irradiation with a 308 nm, 30 ns excimer laser pulse. Heteroepitaxy proceeded from the underlying {001} Si through the carbon containing layer at approximately 5 m/s. Transmission electron microscopy, Fourier transform infrared spectroscopy, high resolution x-ray diffraction, ion channeling, and secondary-ion mass spectrometry were used to characterize the structure and composition. At low concentrations, the films are fully strained and the carbon is substitutional. At concentrations exceeding 1.4 at. % C, SiC precipitates were observed and the substitutional carbon concentration decreased.