The effect of change of voltage acceleration on temperature activation of oxide breakdown for ultrathin oxides

Abstract

We report the effect of change of voltage acceleration on temperature dependence of oxide breakdown for ultra-thin oxides below 6 nm. The time- or charge-to-breakdown (T/sub BD//Q/sub BD/) is directly measured over a wide range of temperatures (-30/spl deg/C to 200/spl deg/C) for several fixed voltages using different area capacitors and long-term stress. Using extensive experimental evidence, we unequivocally demonstrate that this strong temperature dependence of oxide breakdown on ultra-thin oxides is not a thickness effect as previously suggested at least for thickness range investigated in this work. It is a consequence of two experimental facts: 1) voltage-dependent voltage acceleration and 2) temperature-independent voltage acceleration within a fixed T/sub BD/ window. These results provide a coherent picture for T/sub BD/ in both voltage and temperature domains for ultra-thin oxides.