Degenerate Defect States in Metal‐Oxide‐Semiconductor Transistors

The charge carriers trapped by variable defects are a key reliability issue for metal‐oxide‐semiconductor (MOS) transistors. Understanding the microscopic trapping processes is of crucial importance for improving device performance. Here, the trapping and detrapping of charge carriers are investigated by oxide defects via nonradiative multiphonon processes based on the well‐known Huang‐Rhys model. The simulation results to the experimental data is matched in time‐dependent defect spectroscopy, extracting important features of the evolution of defect states with gate bias and temperature. Moreover, the presence of degeneracy‐like defects is revealed with the same energy‐level depth but different localization strength, which could exhibit identical capture and emission rates. These results not only deepen the understanding of charge carrier trapping mechanisms in MOS transistors for bias temperature instability, but also provide insight into the fine analysis of defect species in semiconductor devices.