Universality of power-law voltage dependence for TDDB lifetime in thin gate oxide PMOSFETs

Voltage, polarity and thickness dependencies of time-to breakdown in n-FETs and p-FETs are investigated under inversion and accumulation conditions. The voltage dependence of all the cases is clearly described by a power-law. The voltage acceleration exponents (n) of the power-law of 45 (n-FETs inv.), 40 (n-FETs acc.) and 44 (p-FETs acc.) are independent of thickness. On the other hand, in p-FETs under inversion mode, the exponents (n) are /spl sim/45 for |Vg|>3.8 V and 33 for |Vg|<3.8 V, regardless of thickness. This change in the exponent (n) is explained by a cathode side hydrogen release model.