Si-SiO2 interface-state density was extensively examined for metal-oxide-silicon structures subjected to various kinds of stresses, including bias temperature aging,hot carrier injection, and radiation. The density at surface potentials near 0.7 and 0.4 eV was shown to increase by a ratio of 2:1 for many kinds of stresses and at a ratio of 1:2 for other kinds of stresses. The ratio of p-type to n-type minority carrier recombination Lifetimes was found to decrease by 2:1 for many plasma processes, while for other plasma processes the ratio was 1:2. These ratios of 2:1 and 1:2 may characterize the Si-SiO2 interface.