Experimental Evidence of the Fast and Slow Charge Trapping/Detrapping Processes in High-kDielectrics Subjected to PBTI Stress

A single-pulse technique, with a wide range of pulse times, has been applied to study positive bias temperature instability in high-k nMOSFETs. It is shown that the charging phenomenon includes both fast and slow electron trapping processes with rather well-defined characteristic times, which differ by six orders of magnitude. On the other hand, the poststress charge relaxation cannot be described by a simple detrapping process, which makes identifying the dominant detrapping mechanism complicated.