Novel dual metal gate technology using Mo-MOSIx for advanced MOS device applications

We have successfully demonstrated the feasibility of novel dual metal gate CMOS technology using Molybdenum (Mo) - Molybdenum silicide (MoSix) as gate electrodes. The sputter-deposited α-Si/Mo stack can be transformed into molybdenum silicide after rapid thermal annealing and possess a lower work function value compared with that of pure Mo film. The extracted work function values for pure Mo and MoSix films are 4.935eV and 4.383eV, respectively, especially suitable for advanced transistor structures such as FinFET and ultra-thin-body MOS devices. The thermal stabilities of pure Mo and MoSix films on SiO2 gate dielectric are also demonstrated to be higher than 950°C. Moreover, the proposed dual metal gate technology can preserve gate dielectric integrity since no metal needs to be etched away from the dielectric interface. On the other hand, without using p-type metal silicide as gate electrode, one can expect to achieve a better retardation of boron penetration. These results indicate that Mo and MoSix are promising metal gate candidates for advanced dual metal gate CMOS process.