Elastic Barriers and Formation of Nanoscale Switching Networks

Thin films of silicon oxide (SiOx) are mixtures of semiconductive c-Si nanoclusters (NC) embedded in an insulating g-SiO2 matrix. Tour et al. have shown that a trenched thin film geometry enables the NC to form semiconductive filamentary arrays when driven by an applied field. The field required to form reversible nanoscale switching networks (NSN) decreases rapidly within a few cycles, or by annealing at 600 C in even fewer cycles, and is stable to 700C. Here we discuss an elastic mechanism that explains why a vertical edge across the planar Si-SiOx interface is necessary to form NSN. The discussion shows that the formation mechanism is intrinsic and need not occur locally at the edge, but can occur anywhere in the SiOx film, given the unpinned nanoscale vertical edge geometry.