AFM observation of Si/SiO, interface subjected to electric stress

The evolution of the interface microroughness with current stress in Si MOS capacitors has been studied by means of atomic force microscopy. Much attention has been paid to the periphery of gate oxide films where the breakdown spot is often formed when destructive breakdown occurs. It is observed that the interface roughness is reduced with the progress of the current stress before the destructive breakdown event, indicating local oxidation of Si protrusions on the Si substrate. The results are discussed in connection with interface-state generation and oxygen migration