Infrared and auger spectra of dysprosium silicate films

Dysprosium silicate films, Dy _x Si _y O _z , have been investigated using infrared (IR) and Auger spectroscopy. The films have been formed by oxidizing dysprosium metal films on 5.2-nm-thick silicon dioxide films at a temperature of 600°C. It is shown that the composition of the Dy _x Si _y O _z dysprosium silicate films is close to that of dysprosium pyrosilicate, Dy₂Si₂O₇, and irregular in thickness. On going from the film outer surface to the silicon substrate, the amount of dysprosium decreases and that of silicon bound to oxygen increases. Silicon dioxide, SiO₂, predominates in the layer composition near the silicon substrate. The dielectric leakage current density in the accumulation mode is one order of magnitude lower in the Dy _x Si _y O _z films than in the SiO₂ films of the same equivalent thickness due to the larger physical thickness of the former.