Low voltage stress-induced leakage current in HfO2 dielectric films

The conduction mechanism and the behavior of stress-induced leakage current (SILC) through the HfO2 high-k layers in metal-oxide-semiconductor (MOS) structures have been investigated. Assisted tunneling of electrons via stress-induced interface traps and bulk oxide traps are responsible for the SILC generation in HfO2 dielectric. This trapping process depends on the polarity of the applied gate voltage and oxide thickness. The current conduction mechanism of the HfO2 films is dominated by Poole–Frenkel emission under substrate injection in the region from 1.5 MV/cm to 2.6 MV/cm, confirming that the SILC mechanism is related to the trapping process.