Behavior Of Boron Implanted Into N-Si (100) By Low-Energy (<= 2 Kev) Ion Implantation For A Shallow Junction

We investigated the behavior of boron by varying the B+ ion implantation energy and the rapid thermal annealing (RTA) temperature. The B+ ions were implanted into n-type Si (100), for which the native oxide layer had been removed. The used B+ ion implantation energies were 0.5 keV, 1 keV and 2 keV. The dose was fixed at I X 1015 atoms/cm(2). RTA was performed under a N-2 ambient (760 Torr) at 950 degrees C, 1000 degrees C and 1050 degrees C for 10 s. In order to investigate the boron behavior caused by B+ ion implantation, we measured the junction depth X-j, the dose, the sheet resistance R. and the thickness of silicon oxide layer by using a secondary ion mass spectrometer (SIMS), an ellipsometer, a 4-point probe. By these results, R, in as-implanted samples increased greatly (from 341 Omega/cm(2) to 985 Omega/cm(2) for B+ implantation energies of 0.5 keV and 2 keV, respectively) when Xj increased (from 31 nm for 0.5 keV to 57 nm for 2 keV) because of inactivated dopants. After PTA, the diffusion length Delta X-j was very similar for all ion implantation energies and only changed with variation of the RTA temperature (similar to 35 nm at 950 degrees C, similar to 65 nm at 1000 degrees C and similar to 115 nm at 1050 degrees C). However, R, changed with variations of the ion implantation energy and the RTA temperature and R. decreased after annealing (from 182 Omega/cm(2) for 0.5 keV to 158 Omega/cm(2) for 2 keV at 1050 degrees C). The junction depth X-j depended on the B+ ion implantation energy, but the diffusion length was independent of the B+ ion implantation energy and only depended on the RTA temperature.