The characteristics of hafnium nitride growth on SiO_2 by MOCVD

摘要

Hafnium nitride HfN_x was prepared as gate metal electrode by metal organic chemical vapor deposition (MOCVD) method using tetrakis diethylamido hafnium (TDEAHf) precursor and NH3 gas. As a result, HfN_x films with low levels of carbon and oxygen impurities and smooth interface were formed on SiO_2 substrates. As for the electric property, the resistivity intensively depends on the film composition. Regardless of the preparing conditions, the resistance for all the as-deposited samples was very high due to the non-stoichiometric N-rich Hf nitrides (N/Hf: 1.69). However it decreased greatly after Ar+ ions bombardment because of the nitrogen depletion (N/Hf: 1.28), which resulted from the selective sputtering effect of nitrogen during Ar1" bombardment. In addition, the structure and chemical characteristics of interfacial region was also investigated.