Conduction and switching in SiO sub 2

Experimental results are presented concerning high conduction and switching in Al-SiO sub 2 - Si sandwich structures. The high-conduction state is filamentary, governed mainly by the voltage across the sandwich, and is relatively insensitive to variations in device geometry. Periodic current oscillations are observed for certain combinations of series load resistance and applied voltage. Once the high-conduction state is achieved, it can be maintained at applied voltages below the one required to cause the transition but larger than a min. voltage, which may be related to the min. ionization energy in SiO sub 2. Fluctuations are observed that depend on external circuit configuration, i.e., the load line, and on the ambient temp. A 2-branched current-voltage characteristic can account for the observed behavior. A physical model is presented in an attempt to provide a qualitative explanation of the origin of this form of characteristic. Local damage is evident whenever the high-conduction state is seen (even with a single 50-ns pulse). Electron microscopic analysis of a damaged region is presented.