A dual-metal gate CMOS technology using nitrogen-concentration-controlled TiNx film

A novel dual-metal gate CMOS technology using nitrogen-concentration-controlled TiNx film is described. It is based on a new finding that threshold voltage (V/sub th/) depends on the concentration of nitrogen in the TiNx gate electrode. We found that a V/sub th/ shift as high as -110 mV is controlled by low-energy nitrogen-ion implantation (N I/I) into the titanium nitride film. By using this technology only for nMOSFETs, dual-metal gate CMOS devices are fabricated with a CMOS-process compatibility. A low V/sub th/ is achieved for both n- and pMOSFETs by combining N I/I and a low-doped channel structure.