A NEWLY OBSERVED HIGH-FREQUENCY EFFECT ON THE ESD PROTECTION UTILIZEDIN A GIGAHERTZ NMOS TECHNOLOGY

The standard ESD protection network incorporated onto NMOS integrated circuits is found to turn on partially when subject to valid low volta ge waveforms in high frequency applications. We report on a study of t his phenomenon, and present a physical model that explains our observa tions. It is suggested that the underlying mechanism contributes to th e excellent defense provided by the protection circuitry in convention al usage against damage from large voltage, fast transients.