IRON GETTERING AND DOPING IN SILICON DUE TO MEV CARBON IMPLANTATION

The gettering efficiency for iron of a buried carbon-rich layer formed by 10 MeV carbon implantation with doses in the range of 10(14)-10(16) cm-2 and subsequent annealing was investigated. Iron was additionally introduced into the backside of the silicon wafers by implantation with an energy of 330 keV and doses of 10(12) cm-2 and 10(13) cm-2. Gettering of Fe sets in at a carbon dose of 10(14) cm-2 and is completed at the surface of the wafer for a carbon dose of 10(16) cm-2, both for the highest investigated iron dose of 10(13) cm-2. Moreover, a through-the-wafer inspection of the iron distribution was made. Comparing the dopant properties after MeV implantation of carbon and silicon into silicon with different oxygen content it is shown that carbon related doping is dependent on the presence of carbon and oxygen. The only implantation induced damage in oxygen-rich silicon did not show any doping effect as revealed by self ion implantation of silicon.