A 0.2- mu m contact filling by 450 degrees C-hydrazine-reduced TiN film with low resistivity

Because of the poor step coverage of TiN film by sputter and plasma CVD, the blanket-W for contact plug can not be used beyond 256 Mbit DRAMs. Although a thermal LPCVD-TiN using titanium tetrachloride (TiCl/sub 4/)-ammonia (NH/sub 3/) realizes a conformal deposition, the deposition temperature is too high for devices use (>7000 degrees C). We have developed, for the first time, methylhydrazine (MH) reduced TiN-CVD and succeeded in realizing a low-temperature (<500 degrees C) TiN film with a low chlorine (Cl) concentration that can fill a 0.2 mu m contact hole. A commercial single-wafer LPCVD reactor was used in these experiments. The TiCl/sub 4/-MH reaction proves the capability of low-temperature, low-resistivity, and no-damage contact metallization. The 0.2 mu m contact filling opens the way for the multilevel interconnection of giga-bit devices.<
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