Nature of the defects generated by electric field stress at the Si-SiO2 interface

Abstract

We have characterized the density of states, the capture cross sections, and the annealing properties of the Si-SiO2 interface defects generated during electron injection under high electric field stress. These properties are compared to those of the interface states present in as-oxidized Si-SiO2 structures which are known to be due primarily to the trivalent silicon defects (Pb centers), the main intrinsic defects on thermally oxidized silicon. Although the energetic distribution of the state densities and the annealing properties are similar, we found that the capture cross sections are strongly different. This leads to the conclusion that the interface defects generated by high electric field stress are not strictly identical to Pb centers, but probably ‘‘Pb-like’’ defects. A possible model is discussed.