Nitrogen incorporation into hafnium oxide films by plasma immersion ion implantation

The physics and effects of nitrogen incorporation into hafnium oxide (HfO₂) films were studied in detail. We found that only a trace amount (∼5%) of nitrogen can be introduced into the HfO₂ films by plasma immersion ion-implantation, regardless of implantation dose. We proposed that the nitrogen incorporation is mainly due to the filling of P vacancies in the as-deposited HfO₂ films and the nitridation of suicide bonds at the HfO₂/Si interface. Temperature-dependent capacitance-voltage and current-voltage characteristics measurements indicate that both interface and oxide trap densities were greatly reduced as the results of the nitrogen filling of the O-vacancies and the nitridation of interfacial hafnium suicide bonds. © 2007 The Japan Society of Applied Physics.