MOSFET EVALUATION OF ULTRACLEAN-CVD Si AND SiGe GROWN AT 550t; ON SIMOX

摘要

We grew the 40-nm Si grown at 550℃ on a SIMOX wafer and fabricated a PMOSFET with the 5.9-nm-thick gate SiO_2. The I-V characteristics were almost all equal to those for a PMOSFET directly formed on a SIMOX wafer except for the difference of -0.03 V in the subthreshold voltage. We supposed that the difference was due to point-like defects in the Si and surface contamination on the substrate. We also made a PMOSFET on a 13-nm-thick SiGe well grown on 20-nm-thick Si buffer layer/SIMOX and confirmed the current of holes confined to the SiGe well. The ultraclean LPCVD system was demonstrated to be very useful in growing thin Si and SiGe at the low temperature on SIMOX.