A new method of thin gate SiO₂ reliability characterization

Abstract

Time-dependent dielectric breakdown (TDDB) of thin gate oxides is an important reliability issue of MOS integrated circuits. Breakdown characteristics of thin gate oxides are measured under constant voltage stress (CVS). Effects of the gate voltage and gate oxide area on charge to breakdown Q bd are discussed. The experimental results show that Q bd is not a constant; Q bd depends on both the gate oxide area and stress voltage and cannot act as the breakdown criterion over a wider stress range. Based on experimental results, a novel empirical power law is proposed to characterize thin gate oxide reliability and the correlated parameters are fitted. The empirical power law has been used in extrapolations to obtain Q bd for an arbitrary oxide area and gate voltage. Extrapolated results are in good agreement with those measured at constant voltage, so it is a useful tool for predicting thin gate oxide reliability.