Recent Advances in Understanding Oxide Traps in pMOS Transistors

Oxide traps play an important role in the non-ideal behavior of semiconductors and have been suspected to contribute to the bias temperature instability (BTI), hot carrier degradation, random telegraph and 1/ f noise as well as time-dependent dielectric breakdown. Even though its inadequacy has been repeatedly documented in the literature, charge trapping into these defects is conventionally modeled with extended Shockley-Read-Hall theories. Using the recently suggested time-dependent defect spectroscopy (TDDS), we have demonstrated a number of remarkable features of oxide defects in SiON pMOSFETs, including frequency-dependent capture times, highly biassensitive emission times in so-called switching traps as well as temporary random telegraph noise (tRTN). Theoretical modeling of these features requires nonradiative multiphonon theory and the introduction of metastable states.