Negative Bias Stressing Interface Trapping Centers in Metal Gate Hafnium Oxide Field Effect Transistors Using Spin Dependent Recombination

We combine conventional metal oxide semiconductor (MOS) gated diode measurements and very sensitive electrically detected electron spin resonance (ESR) measurements to detect and identify negative bias temperature instability (NBTI) generated defect centers in fully processed HfO₂ pMOS field effect transistors (pMOSFETs). The spectra were found to be quite different from those generated by NBTI in conventional Si/SiO₂ based devices. The defect spectra generated by long term stressing differ from the short term stressing signals and are somewhat similar to those observed in plasma nitrided oxide Si/SiO₂ based devices. These traces are similar in that their ESR g values are virtually identical. Our results strongly suggest that, in these HfO₂ based devices, NBTI defects are located in the interfacial SiO₂ layer