| 초록 |
NiSi is a promising material for next generation contact applications due to its low resistivity and small Si consumption. For memory devices, especially, highly conformal metal film deposition process is required for silicide contact formation since deep contact holes are used. In the current study, Ni thin films were deposited by plasma enhanced atomic layer deposition (PE-ALD) using bis(dimethylamino-2-methyl-2-butoxo)nickel (Ni(dmamb)2) as a metal precursor. The deposition characteristics and film properties of PE-ALD using NH3 plasma and H2 plasma were comparatively studied as a function of key growth parameters. The saturation growth rate of PE-ALD Ni using NH3 plasma is 2.1Å/cycle at 250℃ which is almost twice than that using H2 plasma (0.9 Å/cycle). Additionally, the lower resistivity and higher purity was observed for PE-ALD Ni using NH3 plasma than H2 plasma. X-ray diffraction and atomic force microscopy analysis have shown that the Ni films from both plasmas are polycrystalline, while the PE-ALD from NH3 plasma has (002) preferred orientations with smaller surface roughness. Differences in chemical compositions and microstructures will be discussed based on the growth mechanism of both cases. |
