Temperature dependence of electronic conduction in thin nitrided oxides

This work reports the temperature dependence of electronic conduction in thin nitrided oxides for temperatures ranging from 298 to 423 K. It was found that the conduction currents in the nitrided oxides have different temperature dependencies from those of conventional thermal oxides. At low electric fields (∼6 MV/cm), the temperature dependencies of the nitrided oxides can be divided into two segments which are attributed to the shallow trap-assisted conduction for temperature less than 400 K and Poole-Frenkel or thermionic emission for temperatures greater than 400 K, whereas the temperature dependence of thermal oxide is governed by exp(-0.143/kT) for the entire temperature range of this study. At high electric fields (∼12 MV/cm), the conduction current of nitrided oxides is mainly governed by Fowler-Nordheim tunneling for temperatures less than 340 K. In studying the temperature dependencies of the electronic trapping in nitrided oxides, we found that the density of trapped charge decreases as large as 27.8% for temperatures rising from 298 to 423 K. It indicates that the density of traps at energy levels less than 0.036 eV (measured from the conduction band of the nitrided oxide) is significantly larger than that of thermal oxides.