Improved characteristics of ultrathin CeO2 by using postnitridation annealing

Abstract

This work demonstrates the improved characteristics of an ultrathin CeO2 dielectric by using the post-N2O plasma treatment with additional rapid thermal N-2 annealing. The CeO2 after the treatment exhibits superior characteristics such as a small effective oxide thickness (similar to2.25 nm), a low leakage current (5.4 x 10(-4) A/cm(2)), a high breakdown electric field (-24 MV/cm), a long projected 10 yr lifetime (-12 MV/cm), a small capacitance-voltage hysteresis (25 mV), and a high barrier height for Frenkel-Poole emission (0.55 eV). These good properties are attributed to the nitrogen incorporation into the dielectric to eliminate the traps after annealing. The postnitridation annealing appears to be a very useful treatment for future ultrathin metal-oxide gate dielectrics. (C) 2004 The Electrochemical Society.