Dependence of leakage mechanisms on dielectric barrier in Cu–SiOC damascene interconnects

Leakage mechanisms of low-dielectric constant (low-k) carbon-doped silicon oxide (SiOC) were investigated in Cu damascene structure integrated with amorphous SiC or SiN as Cu diffusion barrier at low electric fields (0–1.36 MV/cm) and various temperatures (25–250 °C). Conduction mechanisms of SiOC integrated with SiC were found to be different from that with SiN. Schottky emission over a barrier height of 0.70 eV at Ta/SiOC interface dominates in SiC–SiOC structures while Poole–Frenkel emission over a trap potential well of 0.69 eV dominates in SiN–SiOC structures. Traps in the SiN/SiOC interface are the main sources of leakage in Cu low-k damascene structures with SiN barrier.