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TaAlC prepared by thermal atomic layer deposition using tantalum pentachloride (TaCl5) and triethylaluminum (TEA) is successfully demonstrated as work-function metal gate material for the first time. Detailed physical characteristics are demonstrated by X-ray photoemission spectroscopy and X-ray reflectivity. It is found that the as-deposited TaAlC film is consisted of Ta-C, Al-Al and trace Al-C bonds. The TaAlC has reasonable growth rate and linear growth without incubation. Metal-oxide-semiconductor (MOS) capacitor is used to evaluate the effective work-function (EWF). The EWF of TaAlC on HfO2 dielectric can be tunable from 4.65 eV-4.26 eV by process parameter. The lowest EWF which is close to conduction band edge is suitable for high performance FinFET application.

N type metal gate TiAlC film was grown by thermal atomic layer deposition (ALD) technique using titanium tetrachloride (TiCl4) and triethylaluminum (TEA) as precursors for the first time. The physical characteristics of the TiAlC film such as chemical composition, growth rate and crystal morphology were estimated by X-ray photoemission spectroscopy, X-ray reflectivity and X-ray diffraction, respectively. The electrical characteristics of the TiAlC films were investigated by using metal-oxide-semiconductor (MOS) capacitor structure. The effective workfunction can be tunable from 4.46 eV to 4.24 eV by adjusting the growth temperature and the film thickness. The effective workfunction of 4.24 eV is close to the Si conduction band edge. These results show that the TiAlC film is a promising gate metal candidate for the application in FinFET device of 22 nm technology node and beyond.

Metal gate TaAlC film was grown by thermal atomic layer deposition (ALD) technique using tantalum pentachloride (TaCl5) and trimethylaluminum (TMA) as precursors. The effects of growth temperature on the physical and electrical characteristics were estimated by X-ray photoemission spectroscopy, X-ray reflectivity, Grazing incident X-ray diffraction and metal-oxide-semiconductor (MOS) capacitor structure, respectively. It was found that the growth rate increases with growth temperature while the resistivity decreases with growth temperature. All the TaAlC films show cubic microstructure. Superior electrical properties were obtained with TaAlC as gate electrode. The effective workfunction of TaAlC can be tunable from 4.49 eV to 4.74 eV by adjusting the growth temperature and the film thickness. The effective workfunction close to Si mid-gap is suitable for low power FinFET device application.

The role of TiN barrier layer on electrical performance of metal oxide semiconductor (MOS) with Si/SiO2/HfO2/ALD-TiN/ALD-TiAlC structure is investigated. It is found that the effective workfunction of TiN/TiAlC decreases with thinner TiN (in the range of 0[?]3 nm). This is attributed to the lower workfunction of thinner TiN. The gate leakage Jg of the MOS capacitor with TiN barrier is slightly higher than that without TiN, while the equivalent oxide thickness is smaller. The reason is that the insertion of TiN between TiAlC and HfO2 can suppress Al diffusion and boost Ti diffusion into HfO2, leading to smaller EOT and larger leakage current. Moreover, the Jg with and without TiN are both 6 orders of magnitude lower than the traditional poly-Si/SiO2 stacks, which are lower enough for their application in device. These results are helpful to engineering the gate stacks of MOSFET.