RAMAN-SCATTERING OF POROUS STRUCTURE FORMED ON C-IMPLANTED SILICON()

Raman spectra of the porous structure with intense blue emission forme d on C+-implanted silicon were examined using a 488 nm line of Ar+ las er. A Raman peak with full width at half-maximum of 37 cm(-1) was obta ined at about 492 cm(-1). No Raman signals related to the beta-SiC wer e detected. The experimental result indicates that the porous structur e mainly consists of Si nanometer crystallites. The existence of beta- SiC precipitates with nanometer sizes may be beneficial to the reducti on of crystallite sizes and strengthen the Si skeleton, which will lea d to an increase in the energy band gap of Si to the blue light emissi on. Using a model of phonon confinement, the obtained Raman spectra co uld be fitted on the basis of Si quantum crystallites and the average crystallite size was estimated to be 1.4 nm. (C) 1996 American Institu te of Physics.