Sn Spheres Embedded in a SiO2 Matrix: Synthesis and Potential Application As Self-Destructing Materials

We introduce a simple process for the fabrication of SiO2 films embedded with beta-Sn-rich nano/microspheres. Sn spheres with maximum and minimum sizes of 10 mu m (near the SiO2 surface) and 5 nm (at the Si/SiO2 interface) were grown within a 0.7-5.7 mu m-thick SiO2 layer by evaporating SnO powders onto an Si (100) substrate for 1-600 min at 600-900 degrees C and 0.001-5.0 Torr. A possible growth mechanism of these materials is discussed. The current-voltage characteristics of the as-fabricated samples were investigated to identify potential applications. During these tests, small flashes of light and the presence of damaged areas were observed at the oxide surfaces of the samples using an optical camera and a field emission scanning electron microscope, respectively. The electrical breakdown and shutdown of the devices observed in the current-voltage curves were attributed to the destruction of the SiO2 surface. In addition, the current-time responses show that the size of the damaged regions can be controlled by the voltage and duration of the applied stress, and are independent of the size and shape of the electrodes. The present materials thus possess great potential for applications devices.