Thin Solid Films, Vol.498, No.1-2, 75-79, 2006
Effect of NH3 on the fabrication of HfN as gate-electrode using MOCVD
Haffiium nitride HfNx was deposited for gate metal electrode application by MOCVD method using Hf[N(C2H5)(2)](4) (TDEAHf) precursor. Film composition and electrical resistance were analyzed by XPS and four-point probe technique. As a result, NH3 gas, as reactant, plays an important role to the film characteristics. With respect to the growth with NH3 gas, HfNx films with low levels of carbon (< 0.1 at.%) and oxygen (similar to 2 at.%) impurities were formed. However, the resistance was very high and nearly over the measurable order of 108 WE], irrespective of NH3 partial pressure and growth temperature. This was attributed to the formation of N-rich nitride, e.g., Hf3N4 component, which possesses high resistivity. On the other hand, by means of NH3-free growth, metallic films containing about 30% of carbon were directly synthesized. The resistivity was in the range of 10(4) mu Omega-cm at the deposition temperature of 700 degrees C by NH3-free growth. (c) 2005 Elsevier B.V. All rights reserved.