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The resistivity,crystalline structure and effective work function(EWF) of reactive sputtered TaN has been investigated.As-deposited TaN films have an fcc structure.After post-metal annealing(PMA) at 900℃,the TaN films deposited with a N_2 flow rate greater than 6.5 sccm keep their fee structure,while the films deposited with a N_2 flow rate lower than 6.25 seem exhibit a microstructure change.The flatband voltages of gate stacks with TaN films as gate electrodes on SiO_2 and HfO_2 are also measured.It is concluded that a dipole is formed at the dielectric-TaN interface and its contribution to the EWF of TaN changes with the Ta/N ratio in TaN,the underneath dielectric layer and the PMA conditions.
The resistivity, crystalline structure and effective work function (EWF) of reactive sputtered TaN has been investigated. As-deposited TaN films have an fcc structure. After post-metal annealing (PMA) at 900 ° C, the TaN films deposited with a N_2 flow rate greater than 6.5 sccm keep their fee structure, while the films deposited with a N_2 flow rate lower than 6.25 seem exhibit a microstructure change. The flatband voltages of gate stacks with TaN films as gate electrodes on SiO_2 and HfO_2 are also measured. It is said that a dipole is formed at the dielectric-TaN interface and its contribution to the EWF of TaN changes with the Ta / N ratio in TaN, the underneath dielectric layer and the PMA conditions.