Correlation of Dielectric Breakdown and Nanoscale Adhesion in Silicon Dioxide Thin Films

In this work, we introduce a new method that correlates changes in the adhesion and the electrical stress induced defects at the nanometer length scale in dielectric thin films using a conductive atomic force microscope (CAFM). Taking a simple case of silicon dioxide (SiO
₂
), we demonstrate that adhesion at the CAFM tip-oxide contact increases after electrical stress. We also present evidence showing that the polarity dependence of the post-breakdown adhesion is primarily due to the interplay of the CAFM tip with the chemical / ionic bonding and with the electrostatically-charged stress-induced defects (i.e., oxygen ions and vacancies). This new approach can be potentially used to infer the trapped charge densities at the nanometer length scales in dielectrics.