Propagation of the SiO2 breakdown event on MOS structures observed with conductive atomic force microscopy

In this work, for the first time, a conductive atomic force microscope has been used to electrically characterize the degradation and breakdown propagation of stressed ultra-thin (<6 nm) SiO2 films at a nanometric scale. The results show that, although a slight lateral propagation of the degradation is observed before breakdown, the affected area (few hundreds of nm(2)) remains relatively constant. However, breakdown is laterally propagated to neighbor spots, although only in some occasions morphological changes are observed. The breakdown affected area (several thousands of nm(2)) has been found to be strongly related to the hardness of the breakdown event. (C) 2001 Elsevier Science B.V. All rights reserved.