Amorphization processes in ion implanted Si: Temperature dependence

Temperature dependence of amorphization processes in ion-implanted Si has been investigated using Raman spectroscopy together with cross-sectional transmission microscopy. The crystal Si Raman peak decreased and the amorphous Si (a-Si) peak became predominant as the substrate temperture was decreased from 23 °C to — 200°C during 200 keV Si+ ion implantation with a dose of 5 x 1014 cm-2. Based on the analysis of bond angle deviations derived from the a-Si peaks, we have proposed a model in which an accumulation of small defects induces amorphization at low temperatures, while at higher temperatures larger defect complexes are formed and an accumulation of them gives rise to defected amorphous Si.