RAMAN-STUDY OF DAMAGE PROCESSES IN SI-IMPLANTED GAAS()

Ion-induced damage in GaAs as a function of ion dose following 100 keV Si+ implants has been investigated by Raman spectroscopy. A new appro ach for decomposition of Raman scattering intensity on to the crystall ine and amorphous phase components has been used in analysis of Raman spectra. With increasing ion dose the following was observed: a) the w idths of vibrational bands of a-phase significantly increase, while th e width of the LO(T) phonon band of c-phase remains unchanged; b) the longitudinal optical phonon band of c-phase completely dissappears, wh ile the transverse optical phonon mode evolves in to a new band of a-p hase; c) the wavenumbers of all vibrational bands of a- and c-phase sh ift to lower values by similar to 10-15 cm(-1). A number of mechanisms possibly accountable for these shifts were analysed and evaluated.