Influence of bias-temperature stressing on the electrical characteristics of SiOC:H film with Cu/TaN/Ta-gated capacitor

Experiments on bias-temperature stressing, capacitance-voltage measurements, current-voltage characteristics, and time-dependent dielectric breakdown were performed to evaluate the reliability of Cu and low-k SiOC:H integration. A high leakage current of ~8 × 10^sup -10^ to 2 × 10^sup -8^ A/cm^sup 2^ at 1 MV/cm in SiOC:H dielectrics in a Cu-gated capacitor, and a lower 2 × 10^sup -10^ to 5 × 10^sup -10^ A/cm^sup 2^ at 1 MV/cm in a Cu/TaN/Ta-gated capacitor, were observed at evaluated temperatures. The drift mobility of the Cu^sup +^ ions in the Cu/TaN/Ta-gated capacitor was lower than that in a Cu-gated capacitor. A physical model was developed to explain the observed kinetics of Cu^sup +^ ions that drift in Cu-gated and Cu/TaN/Ta-gated capacitors. The electric field in the Cu-gated MIS capacitor in the cathode region is believed to be increased by the accumulation of positive Cu^sup +^ ions, which determines the breakdown acceleration. Good Cu^sup +^ ions drift barrier layers are required as reliable interconnects using thin TaN and Ta layers. Additionally, Schottky emission dominates at low electric fields, E < 1.25 MV/cm, and Poole-Frenkel emission dominates at high fields, E > 1.5 MV/cm. [PUBLICATION ABSTRACT]