Soft breakdown in thin gate oxide - a measurement artifact

Experimental evidence is reported here to show that the often-reported soft breakdown in ultra thin gate oxides under electrical stress is likely an experimental artifact induced by the inability to eliminate the current surge at the moment of the formation of a percolation path. Soft breakdown may not happen in real circuit under normal operation. Thus the percolation model will not be suitable for gate oxide reliability projections. Instead, model calculation of total SILC including multi-trap assisted tunneling at very high trap density will be more relevant to gate oxide reliability.