As-grown HfO2 films by plasma-enhanced chemical vapor deposition (PECVD) were treated by N-2 and NH3 plasma at 70 W and 300 degrees C. The films treated by either N-2 or NH3 Plasma were crystallized at annealing temperature above 800 degrees C, resulting in 200 degrees C higher crystallization temperature than that of HfO2 films without plasma treatment. The capacitors treated at the bottom side of HfO2 by NH3 plasma exhibited the lowest leakage current density, but the highest interface trap density. The capacitors treated at the bottom side of HfO2 by N-2 plasma showed a comparable leakage current density to samples treated by NH3 plasma and the lowest interface trap density. The N-2 plasma- treatment instead of NH3 is a suitable method to improve the reliable characteristics of HfO2 gate dielectric. (c) 2004 Elsevier B.V. All rights reserved.