An observation of breakdown characteristics on thick silicon oxide

We have investigated the current-voltage characteristics of silicon dioxide (SiO₂) with its destruction phenomena and the electric damage which would be introduced by a measurement of leakage current. The samples are oxidized at 820°C~1215°C and their thickness is 10 nm~1650 nm. We have confirmed that the SiO₂ film under the electric stress begins to be damaged at a specific electric field strength. This specific value, ≈8 MV/cm for the 75~100 nm SiO₂, is distinctly lower than the dielectric breakdown value and decreases with increasing SiO₂ thickness. We have found for the first time that the leakage current could suddenly increase up to 100~10000 times near the specific electric field strength if the SiO₂ film was treated above a certain temperature and possesses some thickness. And we suspect that this steep increment of leakage current of SiO₂ is due to the multiplication phenomenon which is activated by the electron´s impact ionization. We have also noticed that the whole current-voltage characteristic of SiO ₂ films is very similar to that of high voltage silicon pn-diodes in the whole range from the very low leakage current to the destruction phenomenon