Ion implantation effects in single crystal Si investigated by Raman spectroscopy

A study of the effects of Ar ion implantation on the structural transformation of single crystal Si investigated by confocal Raman spectroscopy is presented. Implantation was performed at 77 K using 150 keV Ar++ with fluences ranging from 2 x 1013 to 1 x 1015 ions/cm2. The Raman spectra showed a progression from crystalline to highly disordered structure with increasing fluence. The 520 cm-1 c-Si peak was seen to decrease in intensity, broaden and exhibit spectral shifts indicating an increase in lattice disorder and changes in the residual stress state. In addition, an amorphous Si band first appeared as a shoulder on the 520 cm-1 peak and then shifted to lower wavenumbers as a single broadband peak with a spectral center of 465 cm-1. Additionally, the emergence of the a-Si TA phonon band and the decrease of the c-Si 2TA and 2TO phonon bands also indicated the same structural transition from crystalline to highly disordered. The Raman results were compared to those obtained by channeling RBS.