Investigation of thermal atomic layer deposited TiAlX (X = N or C) film as metal gate

• TiAlX (X = N or C) films are developed by thermal atomic layer deposition (ALD) technique as metal gate for CMOS devices.
• The effects of precursor selection and sequence on the atomic layer deposited TiAlX film are investigated.
• The TiAlC film deposited by TiCl4–TMA is rather potential for low power FinFET device application.

TiAlX (X = N or C) films are developed by thermal atomic layer deposition (ALD) technique as metal gate. The TiAlX films are deposited by using four different combinations of precursors: A: TiCl4–NH3–TMA–NH3, B: TiCl4–TMA–NH3, C: TiCl4–NH3–TMA and D: TiCl4–TMA. The physical characteristics of the TiAlX films such as chemical composition, growth rate, resistivity and surface roughness are estimated by X-ray photoemission spectroscopy, scanning electron microscope, four point probe method and atomic force microscopy respectively. Additionally, the electrical characteristics of the TiAlX films are investigated by using metal–oxide–semiconductor (MOS) capacitor structure. It is shown that NH3 presence in the reaction makes the film more like TiAlN(C) while NH3 absence makes the film more like TiAlC. The TiAlC film deposited by TiCl4–TMA has effective work function close to mid-gap of Si, which is rather potential for low power FinFET device application.