The generation of interface states and oxide electron traps in thermal SiO2 layers by sputtering metallization was investigated. The dependence of the samples upon electric field and temperature during the sputter process was observed. The interface state density spectra revealed narrow distributions indicating an increased density of band edge states. In the upper part of the Si band gap a peak was observed due to the generation of a particular interface defect site. Three bulk defect centers were found as identified by their capture cross sections of the order of 10-16, 3 x 10-17 and 3 x 10-18cm2. The first one was associated with radiation induced neutral centers and was a feature of oxides metallized by sputtering. The other two traps were believed to be related to defects like SiOH and H2O. Post-metallization annealing resulted in a reduction of the density of the oxide and interface traps and a broadening of the interface trap spectra.

Sputter-Metallization-Induced Electronic Defects in Thermal SiO2. S.Alexandrova, A.Szekeres: Physica Status Solidi A, 2001, 187[2], 499-506