Effects of carbon implantation on generation lifetime in silicon

Abstract

In this study, we present characterization of metal–oxide–silicon (MOS) capacitors fabricated on carbon (C12) implanted Si substrates. Carbon was implanted at an energy of 50 keV with doses ranging from 1×1012 cm−2 to 4.1×1015 cm−2. Metal–oxide silicon capacitors were fabricated and used to determine the MOS capacitance–voltage (C–V) and capacitance–time (C–t) behavior. These measurements revealed a strong correlation between carrier lifetime and the C dose. Degradation in lifetime was observed for C dose levels as low as 4×1012 cm−2. At C doses equal to and above 6.4×1013 cm−2, extremely low generation lifetimes were obtained (∼10−7 s). On the other hand, for C dose levels higher than 2.7×1014 cm−2, a low accumulation capacitance was observed at high frequencies and attributed to hole traps. Below this dose, both flatband voltage and interface trap density of the C implanted samples were comparable to those of the monitors.