Positive charge generation due to species of hydrogen during NBTI phenomenon in pMOSFETs with ultra-thin SiON gate dielectrics

Abstract

Negative bias temperature instability (NBTI) of pMOSFETs with ultra-thin SiON gate dielectrics was investigated. We focused our attention on the behavior of hydrogen atoms released from the interface under NBT stress. From the transient characteristics of pMOSFETs after NBT stresses were stopped, it was found that a portion (60%, in our case) of hydrogen atoms released by the NBT stress remain in a 1.85-nm-thick NO-oxynitride gate dielectric. The existence of the hydrogen in the gate dielectric was shown to lead to the generation of positive charges.