Real-time characterization of free-carrier absorption during epitaxial Si p-layer growth

We have applied IR attenuated total reflection spectroscopy (ATR) to characterize free-carrier absorption during epitaxial Si p-layer growth by plasma-enhanced chemical vapor deposition. In the early stage of the growth, there are no detectable free carriers in the epitaxial p-layer, whereas we find a drastic increase in free-carrier concentration after terminating the plasma for the growth. We attribute this effect to a reduction in surface defects present during the epitaxial growth. The carrier concentration and mobility for the Si p-layer deduced from an ATR analysis were in excellent agreement with those estimated by Hall measurement. The results demonstrate the feasibility of real-time ATR to characterize the dynamics of carrier generation during doped semiconductor growth. (C) 2003 American Institute of Physics.