Arsenic and phosphorus double ion implanted source/drain junction for 0.25and sub-0.25-μm MOSFET technology

An arsenic and phosphorus double implanted source/drain junction is proposed for 0.25- and sub-0.25-μm NMOSFET technology. Arsenic is for the shallow high concentration region beneath the silicide, and phosphorus is for the slightly deeper junction to increase junction quality and to reduce junction capacitance. The arsenic and phosphorus double implantation is performed after sidewall formation. The double implanted source/drain junction shows a drastic reduction of reverse leakage current and little effect on the short channel characteristics compared with an arsenic only implanted device. Moreover, the circuit performance is improved by about 2.5%.