Charge transport mechanism in periodic mesoporous organosilica low-k dielectric

Abstract

Periodic mesoporous organosilicas are promising insulating materials for multilevel interconnects of integrated circuits because of their unique structural and mechanical properties. Therefore, understanding of their electrical characteristics, particularly the charge transport mechanism, is important. It is generally accepted that the thin dielectric film charge transport is limited by the Frenkel effect. In our work, the charge transport of the periodic mesoporous organosilica structure is analyzed with four volume-limited charge transport models. It is established that the Frenkel model of Coulomb trap ionization, the Hill-Adachi model of overlapping Coulomb potentials and the Makram-Ebeid and Lannoo model of multiphonon isolated traps ionization quantitatively, do not describe the charge transport of the periodic mesoporous organosilica low-k dielectric. The Nasyrov-Gritsenko model gives a consistent explanation of the charge transport of the periodic mesoporous organosilica low-k structure at different temperatures with the trap concentration N = 5.4 × 1020 cm−3 and effective mass m* = 0.82 me. The thermal trap energy Wt = 1.6 eV and the optical trap energy Wopt = 3.2 eV obtained from the simulation by the Nasyrov-Gritsenko model correspond to the Si-Si defect.