Growth of Hafnium Oxide Films by Metalorganic Chemical Vapor Deposition Using Oxygen-Free Hf[N(C_2H_5)_2]_4 Precursor and Their Properties

摘要

Hafnium oxide films were deposited on silicon substrates at deposition temperatures ranging from 190 to 500 deg C by metalorganic chemical vapor deposition. An oxygen-free precursor, Hf[N(C_2H_5)_2]_4, and 02 gas were used as starting materials. The reaction-limited deposition of hafnium oxide films fabricated with Hf[N(C_2H_5)_2]_4 was observed for wide temperature region compared with that with the conventional alkoxide precursor. Concentration of contaminated elements, such as carbon, nitrogen and hydrogen, decreased with increasing the deposition temperature, and amorphous films were obtained up to 450 deg C. Flat surface was obtained between 280 and 450 deg C. Reduction of hysteresis in capacitance-voltage curve and the increase of the accumulation capacitance were both achieved by the high temperature deposition. Hf[N(C_2H_5)_2]_4 is a unique precursor which can produce amorphous hafnium oxide films having very flat surface even at high deposition temperature of 400 and 450 deg C together with the reduction of the contamination elements.