| 摘要 |
A hot carrier lifetime of a MOS transistor is estimated, depending on model formulas: 1/tau=1/tau<SUB>0</SUB>+1/tau<SUB>b</SUB>; tau<SUB>b</SUB>∝1<SUB>sub</SUB><SUP>-mb</SUP>.I<SUB>d</SUB><SUP>mb-2</SUP>.exp(a/|V<SUB>bs</SUB>|), where tau denotes a lifetime, I<SUB>sub </SUB>denotes a substrate current, I<SUB>d </SUB>denotes a drain current, V<SUB>bs </SUB>denotes a substrate voltage, tau<SUB>0 </SUB>denotes a lifetime at the time the substrate voltage V<SUB>bs</SUB>=0, tau<SUB>b </SUB>denotes a quantity representing deterioration of a lifetime at the time the substrate voltage |V<SUB>bs</SUB>|>0, and mb and 'a' are model parameters. Furthermore, a parameter Age representing a cumulative stress quantity is calculated depending on model formulas: Age=Age<SUB>0</SUB>+Age<SUB>b</SUB>; Age<SUB>b</SUB>=∫1/H<SUB>b</SUB>[I<SUB>sub</SUB><SUP>mb</SUP>.I<SUB>d</SUB><SUP>2-m</SUP>].exp(-a/|V<SUB>bs</SUB>|)dt, where t denotes time, H<SUB>b </SUB>is a model parameter, Age<SUB>0 </SUB>denotes a parameter representing a cumulative stress quantity at the time the substrate voltage V<SUB>bs</SUB>=0, and Age<SUB>bs </SUB>denotes a quantity representing an increase of the cumulative stress quantity at the time the substrate voltage at |V<SUB>bs</SUB>|>0. Thereby, a lifetime in actual use is determined with accuracy even when a substrate voltage is applied, and circuit characteristic degradation is simulated with high accuracy.
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