Analysis of defects at the interface between high-k thin films and (1Â 0Â 0) silicon

Paramagnetic defects in atomic layer deposition grown aluminium oxide thin films have been studied using electron paramagnetic resonance. Initial spectra indicate the presence of Si-db, Pb0 and Pb1 defects, previously observed in Si/SiO2 structures. We show that the Si-db defect is located in the substrate only. We quantify the unpassivated Pb-type defect density and show that this can be reduced by a pre-deposition nitridation step. However, forming gas annealing at temperatures up to 550 °C causes no further reduction in defect density; this may be related to the low deposition temperature, which causes a spread in passivation activation energies.