Ultimate limit for defect generation in ultra-thin silicon dioxide

Experimental and theoretical investigations are reported for defect generation by electrical stress in silicon dioxide and for the critical number of defects necessary to trigger destructive breakdown. Experimental evidence is presented showing that the critical number of defects reaches a limit when the oxide thickness is reduced below 2.7 nm. Percolation calculations are shown ta be consistent with this oxide thickness limit representing the ''effective size'' of one defect spanning the oxide, connecting anode and cathode together. Also, these calculations show that not all of the defects are capable of triggering a destructive breakdown event. (C) 1997 American Institute of Physics.