Evaluation of electron traps in SiNx by discharge current transient spectroscopy: verification of validity by comparing with conventional DLTS

Discharge current transient spectroscopy (DCTS) is a promising technique for detecting the trap level and density in dielectrics because it is based on a simple emission process. In order to confirm the validity of DCTS, we compare the results from the conventional deep-level transient spectroscopy (DLTS) technique for samples of CVD-grown silicon nitride (SiNx) films. Results indicated that a trap level, about 0.6 eV below the energy level of the conduction band edge in the SiNx thin films estimated by DCTS is in good agreement with that obtained from DLTS analysis, and it is found that the trap density increases with the decreasing N/Si ratio in the SiNx film. As a proposed estimation for energy level in defects, it will be originated from hydrogen-incorporated defects in the SiNx matrix. This study demonstrates that the DCTS method will be a useful electrical method for the evaluation of defects.