Improvement in antimony-doped ultrashallow junction sheet resistance by dopant pileup reduction at the SiO2/Si interface

Ultrashallow low-resistive junction formation has been investigated for sub -100-nm metal oxide semiconductor field effect transistors (MOSFETs) using low-energy Sb implantation and the rapid thermal annealing (RTA) technique. The Sb pileup at the Si/SiO2 interface and the resulting dopant loss obser ved in the furnace annealing cases was reduced by the RTA technique. As a r esult, the sheet resistance of 19-nm-deep junctions was decreased to 0.84 k Omega/sq. By increasing the implantation dose to 1 x 10(14) cm(-2), a junc tion depth of 24 nm and sheet resistance of 0.45 k Omega/sq. were obtained. In the case of As, the pileup was not suppressed even with RTA. These resu lts indicate that Sb is superior to As as a dopant for ultrashallow extensi on formations.