Characterization methods for plasma process-induced damage to dielectric films with pre-existing defects

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Abstract Interlayer dielectric (ILD) films contain various defect structures that originate from species in precursor gases during deposition processes, as well as from plasma irradiation during manufacturing known as plasma-induced damage (PID). This study clarifies how pre-existing defects in ILD (SiO2) films influence PID analysis. We investigated electrical characteristics changes after Ar and He plasma exposures using Al/SiO2/Si devices. The statistical current–voltage (I–V) analysis assigned the significant distortion of intrinsic I–V curves and an increase in the dielectric breakdown voltage of the SiO2 films after plasma exposure, which leads to an erroneous PID assessment. Constant-voltage stress (CVS) tests were applied to address how the profiles of defects—created by PECVD, PID, and CVS—impacts reliability lifetime prediction. Time evolutions of the current under CVS were found to depend on the profile, giving the precise and correct PID assessment.