High-k Dielectrics and Dual Metal Gates: Integration Issues for New CMOS Materials

Abstract

ABSTRACTSeveral metal and conducting metal nitride candidates were investigated for alternative gate electrode applications in future complimentary metal-oxide-semiconductor (CMOS) devices. High frequency capacitance-voltage (CV) measurements were performed on n-MOS and p-MOS capacitors with Al, Ta, TaN, TIN, or W2N gates and ultra-thin SiO2/Si3N4 dielectric stacks. The work functions of Al and Ta were close to the conduction band of Si as expected while all the metal nitrides had work functions slightly above mid-gap. The thermal stability of the metal nitrides and the metal/dielectric interfaces was studied by Auger electron spectroscopy (AES) following rapid thermal annealing (RTA). Integration requirements for dual metal gate electrodes in future CMOS devices are discussed.