Characterization of Temperature Dependence for HfO_2 Gate Dielectrics Treated in NH_3 Plasma

摘要

For the first time, the characteristics and temperature dependence of electrical properties for ultrathin HfO_2 gate dielectrics treated in NH_3 plasma after deposition were investigated. After this treatment, significant nitrogen incorporation at the HfO_2/silicon interface (interfacial layer) was examined by Auger electron spectroscopy. Moreover, the formation of Hf-N bonding and the suppression of Hf-Si bonding were observed from electron spectroscopy for chemical analysis spectra. The activation energy of charge trapping reflected in the current-voltage characteristics was effectively reduced, which led to improved hysteresis and its weaker temperature dependence in HfO_2 gate dielectrics treated in NH_3 plasma.