The Raman Spectrum of Carbon in Silicon

Abstract

Raman spectroscopy is used to characterize carbon-doped silicon samples prepared by ion implantation and pulsed laser annealing. Sharp lines are observed in the Raman spectra due to the ¹²C local mode at 604±1 cm^-1 and the ¹³C local mode at 586±1 cm^-1. Identical spectra are obtained from a given carbon implant whether it is annealed using a 10 ns pulsed ruby laser or the significantly longer pulse of an R6G dye laser. It is shown that Raman spectroscopy has sufficient sensitivity to detect striated carbon distributions in as-grown commercial silicon. Finally, at high carbon density, where the local modes begin to broaden in the implanted and laser-annealed samples, a disorder-induced first-order Raman spectrum is observed produced by the mass defect of the substitutional carbon.