Increase of leakage current and trap density caused by bias stress in silicon nitride prepared by photo-chemical vapor deposition

Leakage current at low electric fields in silicon nitride (SiNx) prepared by photo-chemical vapor deposition is increased by bias stress. Discharging current transient spectroscopy (DCTS) for determining the density and energy distribution of traps in insulators is applied to the study of the change of traps by bias stress. After holes of 2.6×10-2 C/cm2 are injected into SiNx, the densities of single-level traps (approximately 0.80 eV) and energetically distributed traps located between 0.83 eV and 0.90 eV above the top of the valence band in SiNx increase, which could result in the increase of leakage current.